9th Barrande-Vltava French-Czech Chemistry Meeting

Chemical Science, Dalton Transactions, Organic and Biomolecular Chemistry and Physical Chemistry Chemical Physics are proud to sponsor the 9th Barrande-Vltava French-Czech Chemistry Meeting taking place on 27-28 August 2018 in Strasbourg, France. The organizing committee is led by Stéphane Bellemin-Lapponez and the meeting aims to provide French and Czech researchers with an informal setting to exchange ideas and initiate collaborations.

This meeting will focus on all aspects of molecular and supramolecular chemistry, as well as applications in medicinal chemistry and imagery. The program includes plenary lectures from experts such as Didier Bourissou (University Paul Sabatier), Jean-Marie Lehn (Institute of Supramolecular Science and Engineering) and Irena G. Stara (Institute of Organic Chemistry and Biochemistry). A full list of speakers can be found here.

Don’t miss out on your chance to attend this meeting – Register now!

 

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

CURO-Pi III: a conference on the chemistry & physics of curved pi-conjugated molecules

Chemical Science is proud to sponsor CURO-Pi III, taking place at the University of Oxford in the UK on 5-7 September 2018. This international symposium, chaired by Professor Harry Anderson, is on the synthesis and application of curved organic pi-molecules and materials.

With an exciting list of international speakers, including the keynote speaker Kenichiro Itami (Nagoya University), this conference will cover the synthesis and properties of non-planar aromatics and curved pi-systems, and extend the application of these compounds in fields such as electronics and biology.

Don’t miss out on your chance to attend this symposium – last few places remaining! Register by 31st July.

 

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Surface Charge Determines Success of Encapsulating Proteins into a ZIF-8 Metal Organic Framework

Australian scientists from The University of Adelaide and Graz University of Technology recently made a breakthrough in protein chemistry. They revealed that the key to successfully encasing proteins into metal organic frameworks (MOFs, a family of highly porous organic-metal coordination molecules) was the surface charge of the proteins. Their work was recently published in Chemical Science.

Encapsulating proteins into MOFs, a process termed “biomimetic mineralisation”, is an efficient way to protect and preserve proteins. This process is typically initiated by mixing the proteins and the precursors of a MOF. The MOF starts to grow at the protein surface and eventually fully covers the protein. As the growth of the MOF begins with nucleation on the protein surface, the surface properties play an important role in controlling the rate and quality of the encapsulation. Unfortunately, the interplay between protein surface and MOF growth has not been well understood, leading to inefficient reactions that require excess MOF precursors and long reaction times.

The authors demonstrated for the first time that the surface charge is one of the key factors that affects the possibility of biomimetic mineralisation. Specifically, they discovered that proteins with strongly negative charged surfaces, such as pepsin and bovine serum albumin, were able to be spontaneously incorporated into ZIF-8 (a benchmark MOF). Conversely, those with naturally positively charged or slightly negatively charged surfaces, including haemoglobin, were incapable of forming composites with ZIF-8. The authors further showed that changing the surface charge could allow or prohibit the encapsulation. For example, after reacting the lysine groups of haemoglobin with succinic anhydride, the surface of haemoglobin became more negative and ZIF-8 could now readily wrap around the protein (Figure 1). The surface potential threshold to induce biomimetic mineralisation was determined to be -30 mV.

Figure 1. Schematic illustrations of the biomimetic mineralisation of haemoglobin and bovine serum albumin. Haemoglobin with slightly negatively charged surface is unable to form composites with ZIF-8, but becomes active after succinylation or acetylation to make its surface strongly negatively charged. On the contrary, bovine serum albumin with a strongly negatively charged surface readily combines with ZIF-8, but loses its activity when its surface becomes less negatively charged via amination.

The mechanism of the aforementioned observations was attributed to the electrostatic attraction between the protein surface and Zn2+, one of the MOF precursors. The more negatively the surface is charged, the more easily the Zn2+ will attach to and accumulate at the protein surface. The adsorbed Zn2+ ions then serve as the nucleation sites for the MOF to grow around the protein. This hypothesis is proven by a number of control experiments and also validated by computational studies.

This study highlights the surface potential of a protein as a critical factor in its ability to induce biomimetic mineralisation with MOFs. The conclusions could potentially be extended to biomolecules other than proteins (e.g. viruses and cells) to facilitate their integration with various MOFs.

 

To find out more please read:

Protein Surface Functionalisation as A General Strategy for Facilitating Biomimetic Mineralisation of ZIF-8

Natasha K. Maddigan, Andrew Tarzia, David M. Huang, Christopher J. Sumby, Stephen G. Bell, Paolo Falcaro and Christian J. Doonan

Chem. Sci., 2018 , DOI: 10.1039/c8sc00825f

About the blogger:

Tianyu Liu obtained his Ph.D. (2017) in Physical Chemistry from University of California, Santa Cruz in United States. He is passionate about scientific communication to introduce cutting-edge research to both the general public and scientists with diverse research expertise. He is a blog writer for Chem. Commun. and Chem. Sci. More information about him can be found at http://liutianyuresearch.weebly.com/.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Outstanding Reviewers for Chemical Science in 2017

We would like to highlight the Outstanding Reviewers for Chemical Science in 2017, as selected by the editorial team, for their significant contribution to the journal. The reviewers have been chosen based on the number, timeliness and quality of the reports completed over the last 12 months.

We would like to say a big thank you to those individuals listed here as well as to all of the reviewers that have supported the journal. Each Outstanding Reviewer will receive a certificate to give recognition for their significant contribution.

Dr Lutz Ackermann, Georg-August-Universitaet, ORCID: 0000-0001-7034-8772
Dr Mircea Dinca, MIT, ORCID: 0000-0002-1262-1264
Professor Frank Glorius, University of Muenster
Dr Takashi Hisatomi, The University of Tokyo, ORCID: 0000-0002-5009-2383
Professor Rei Kinjo, Nanyang Technological University, ORCID: 0000-0002-4425-3937
Professor Jun Kubota, Fukuoka University
Professor Akihiko Kudo, Tokyo University of Science
Dr Armido Studer, WWU Muenster, ORCID: 0000-0002-1706-513X
Dr Bo Tang, Shangdong Normal University, ORCID: 0000-0002-8712-7025
Dr Jay Winkler, California Institute of Technology

We would also like to thank the Chemical Science Board and the general chemical sciences community for their continued support of the journal, as authors, reviewers and readers.

If you would like to become a reviewer for our journal, just email us with details of your research interests and an up-to-date CV or résumé. You can find more details in our author and reviewer resource centre.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Customised peptides via nickel/photoredox-catalysed bioconjugation

Proteins have an expansive utility in the structure, function, replication and regulation of all cells, and developing tools to study each role is to the benefit of our continued health and wellbeing. One tool is protein bioconjugation, the covalent pairing of a molecule with a protein. Molecule-protein combinations are endless, provided there are efficient methods available to couple molecules with amino acids. Among bioconjugation methods, cysteine functionalisation is a popular choice because the primary thiol is highly nucleophilic thus aiding chemoselectivity. Furthermore, cysteine is rare, reducing the likelihood of many competing, reactive residues.

Transition metal catalysed transformations are uncommon in bioconjugations, despite prominence in other areas of synthetic chemistry. This is because only the most robust methods can overcome the challenges of this chemistry: the solubility of substrates in solvents other than aqueous media, the presence of other amino acids bearing reactive functional groups, and the requirement for low temperatures, low concentrations and mild pH to preserve protein structure.

Catalytic cycle for the nickel/phororedox catalysed synthesis of cysteine bioconjugates

Catalytic cycle for the nickel/phororedox catalysed synthesis of cysteine bioconjugates

A group of researchers from the University of Pennsylvania headed by Professor Gary Molander have developed a bioconjugation method in which aryl halides are cross-coupled with cysteine residues in peptides. Two complexes catalyse the reaction in two connected cycles: the photoredox cycle by a ruthenium-bipyridine complex, and the catalytic cycle by a nickel-bipyridine complex.

The reaction is efficient at room temperature and does not require prior functional group protection. The reaction can also be performed under dilute conditions (10 mM) and on gram scale (3.5 mmol). The scope table includes more than 35 reactions coupling a broad range of aryl halides with small peptides (4 and 9 amino acids) and biologically relevant molecules such as coenzyme A and sulphur-containing pharmaceuticals.

Protecting-group free functionalisation of small peptides under dilute conditions using nickel and ruthenium photoredox catalysis for cysteine functionalization

Protecting group free functionalisation of small peptides under dilute conditions

Included in the reaction scope are a number of substrates which highlight how this work can adapt to established techniques for studying proteins. Coupling of a coumarin generates a fluorescent molecule, which could be used to study the cellular localisation of a protein. Reaction with an aryl-bound biotin derivative demonstrates that affinity tags can be coupled, and utilising aryl-containing pharmaceutical agents is relevant to the synthesis of antibody-drug conjugates.

With this research the authors have contributed a robust catalytic system, which convincingly shows the value of combining a transition metal and photoredox catalyst to functionalise cysteine residues in biomolecules. A necessary next step for this chemistry, and no small task, is to further optimise the reaction conditions for whole proteins.

Read the research article:

Scalable thioarylation of unprotected peptides and biomolecules under Ni/photoredox catalysis

Chem. Sci., 2018, DOI: 10.1039/C7SC04292B

Brandon A. Vara, Xingpin Li, Simon Berritt, Christopher R. Walters, E. James Petersson, Gary A. Molander.


About the Author: 

Zoë Hearne is a PhD candidate in chemistry at McGill University in Montréal, Canada, under the supervision of Professor Chao-Jun Li. She hails from Canberra, Australia, where she completed her undergraduate degree. Her current research focuses on transition metal catalysis to effect novel transformations, and out of the lab she is an enthusiastic chemistry tutor and science communicator.

 

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Chemical Science is moving to weekly issues!

A gold open-access journal that’s free to read & free to publish in

We have exciting news here at Chemical Science! From 2018, the journal will be moving from publishing monthly issues to weekly issues. This is one of the biggest changes to the journal since it was launched in 2010.

Why are we doing this? By publishing weekly issues, we’ll be able to make our articles more accessible to keep up with the large number of articles we currently publish. With the journal being free to access, it would be a shame for the community to miss the latest exceptional findings due to less frequent, larger issues.

What are the benefits for the chemical sciences community? For our readers, it will be easier to find the latest relevant articles, with weekly table-of-contents alerts and a shorter contents list for each issue. For our authors, articles will be assigned page numbers more quickly and will be indexed in databases such as PubMed Central® sooner.

You can learn more about this change in our Editorial by Executive Editor, May Copsey, published in the first ever Chemical Science weekly issue!

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Meet Vincent Artero: Chemical Science Associate Editor

We are delighted to welcome Professor Vincent Artero as Chemical Science Associate Editor, handling submissions in the area of energy.

Vincent Artero graduated from the Ecole Normale Supérieure (Ulm) and the University Pierre et Marie Curie (Paris 6). He received his Ph.D. in 2000 under the supervision of Professor A. Proust and Professor P. Gouzerh. His doctoral work dealt with organometallic derivatives of polyoxometalates. After a postdoctoral stay at the University of Aachen (Aix la Chapelle) with Professor U. Kölle, he joined in 2001 the group of Professor M. Fontecave in Grenoble where he obtained a position in the Life Science Division of the CEA.

Since 2016, he leads the SolHyCat group as Research Director in the Laboratory of Chemistry and Biology of Metals (a research unit cooperated by CEA, CNRS and Univ. Grenoble Alpes) in Grenoble. Vincent Artero received the “Grand Prix Mergier-Bourdeix de l’Académie des Sciences” in 2011. In 2012, he was granted with a Consolidator Grant from the European Research Council (ERC). He currently acts as Chair of the Scientific Advisory Board of the ARCANE Excellence Laboratory Network (LABEX) for bio-driven chemistry in Grenoble and co-chair of the French Research Network (GDR) on solar fuels.

His current research interests are in the structural and functional modelisation of hydrogenases, the design of artificial organometallic proteins and the photo- and electro-production of hydrogen. Vincent is keen to receive submissions in his area of expertise.  Below is a list of recent Chemical Science articles published within the energy-related field – all free to read. We hope you enjoy them!

Porous dendritic copper: an electrocatalyst for highly selective CO2 reduction to formate in water/ionic liquid electrolyte
Tran Ngoc Huan, Philippe Simon, Gwenaëlle Rousse, Isabelle Génois, Vincent Artero and Marc Fontecave
Chem. Sci., 2017,8, 742-747
DOI: 10.1039/C6SC03194C

Ligand effect on the catalytic activity of porphyrin-protected gold clusters in the electrochemical hydrogen evolution reaction
Daichi Eguchi, Masanori Sakamoto and Toshiharu Teranishi
Chem. Sci., 2018, Advance Article
DOI: 10.1039/c7sc03997b

A matrix of heterobimetallic complexes for interrogation of hydrogen evolution reaction electrocatalysts
Pokhraj Ghosh, Shengda Ding, Rachel B. Chupik, Manuel Quiroz, Chung-Hung Hsieh, Nattami Bhuvanesh, Michael B. Hall
and Marcetta Y. Darensbourg
Chem. Sci., 2017,8, 8291-8300
DOI: 10.1039/c7sc03378h

Site-isolated manganese carbonyl on bipyridine-functionalities of periodic mesoporous organosilicas: efficient CO2 photoreduction and detection of key reaction intermediates
Xia Wang, Indre Thiel, Alexey Fedorov, Christophe Copéret, Victor Mougel and Marc Fontecave
Chem. Sci., 2017,8, 8204-8213
DOI: 10.1039/C7SC03512H

You can submit your high quality research in the area of energy to Vincent Artero’s Editorial Office.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Old and new spectroscopic techniques team up to decipher intricate alkaloids

Cutting-edge strategies set to increase our access to chemical space after researchers use them to verify unprecedented structures

Scientists have identified the structures of two marine natural products that were previously considered too complicated to characterise.1 A combination of well-known spectroscopic tools and new experiments probing orientation-dependant bonding allowed the team to unpick the structures.

Source: © Royal Society of Chemistry
Structures of caulamidines A (left) and B (right)

Natural products are a rich source of pharmacologically-active compounds. The problem is: they are often difficult to purify and identify.

Gary Martin, of Merck Research Laboratories in the US, and Kirk Gustafson, from the US National Cancer Institute, have been studying and characterising natural products for years. ‘There has been a continuing flow of incorrectly reported complex natural product structures into the published literature … at present, there are more than 1200 structure revision papers. Stopping investigators from reporting incorrect structures in the first place will free up their time to pursue and identify new molecular entities,’ they say.

Read the full story by Hannah Kerr on Chemistry World.

1 D J Milanowski et al, Chem. Sci., 2017, DOI: 10.1039/c7sc01996c (This paper is open access.)

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

What’s left isn’t always right in total synthesis

Using detective skills that would make Hercule Poirot proud, researchers in the US have solved a longstanding mystery around the absolute configuration of natural product (+)-frondosin B.1

Source: Royal Society of Chemistry Summary of the enantioselective frondosin B syntheses reported to date

(+)-Frondosin B is part of a family of marine sesquiterpenes found in underwater sponges that exhibit anti-inflammatory properties and have potential applications in anticancer and HIV therapy. Starting with Samuel Danishefsky’s route in 2001,2 there have been 5 total syntheses of (+)-frondosin B. However, due to a discrepancy in the optical rotation of the final product during Dirk Trauner’s 2002 synthesis,3 which was observed to have S rather than the expected R configuration, there has been a fierce debate in the synthetic community about the true stereochemistry at C8 in the natural product. After more than decade of attempts by synthetic organic chemists to explain this, particularly focused on different inversion processes, no definitive answer had arisen.

Read the full story by Jason Woolford on Chemistry World.

1 L A Joyce et al, Chem. Sci., 2017, DOI: 10.1039/c7sc04249c (This paper is open access.)

2 M Inoue et al, J. Am. Chem. Soc., 2001, 123, 1878 (DOI: 10.1021/ja0021060)

 

 

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Benchmark for molecular machine learning

A team at Stanford University in the US has developed a benchmark for machine learning in chemistry. By providing a consistent way to test different techniques across a range of chemical data, it aims to accelerate the growth of this new type of scientific problem-solving.

Source: Royal Society of Chemistry
MoleculeNet curates multiple public datasets, establishes metrics for evaluation, and offers high quality open-source implementations of multiple previously proposed molecular featurisation and learning algorithms (released as part of the DeepChem open source library)

Machine learning methods train a computer to efficiently get from raw data to already-known answers. Once the expected results are consistently reproduced, the software is ready to perform the same task with entirely new data. To fairly compare different learning approaches, research groups around the globe need to train and test their methods using a shared set of problems. Reference databases already exist for images and text; MoleculeNet, an extension of the DeepChem project, provides such a benchmark for chemistry.

Read the full story by Alexander Whiteside on Chemistry World.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)