Organic & Biomolecular Chemistry Blog

A sensing system to detect cysteine (Cys), an essential amino acid, has been developed by scientists in the US and China. Elevated levels of Cys have been associated with neurotoxicity, while Cys deficiency is involved in a number of other disorders.

The sensing system works as a fluorescent chemodosimeter, which displays discrimination for cysteine over commonly occurring analytes that would be expected to co-exist in real samples, such as homocysteine and glutathione. Moreover, the system is desirable in that it displays off-to-on response to the target analyte and does so at a desirable long wavelength, which minimises potential interference by endogenous chromophores.

Due to its simplicity and very high selectivity, this chemodosimeter can be used to detect Cys at physiological levels.

Highly rated by the reviewers and Editorial office alike, this article has been selected as ‘Hot’ and will be FREE to access for the next 4 weeks – why not read it now!

A seminaphthofluorescein-based fluorescent chemodosimeter for the highly selective detection of cysteine
Xiaofeng Yang, Yixing Guo and Robert M. Strongin
Org. Biomol. Chem., 2012, Advance Article
DOI: 10.1039/C2OB25178G, Communication

In this OBC ‘Hot paper’ John C. Vederas and coworkers describes studies on a key enzyme (DscC) in the biosynthesis of the important antibiotic D-cycloserine – commonly used against Mycobacterium tuberculosis when resistance to other antibiotics is observed.

The enzyme is proposed to be an epimerase based on sequence similarity to a known enzyme DapF (diaminopimelate epimerase), and the authors show that DscC indeed displays the predicted activity, namely O-ureidoserine racemization.

The determination of the 3D stucture of the enzyme is underway.

‘Comparison of the enzymatic residues that are responsible for recognition of the non-reacting distal site of the enzyme could lead to the ability to rationally design enzymes that can induce epimerization of other amino acids’, conclude the authors.

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Characterization of DcsC, a PLP-independent racemase involved in the biosynthesis of D-cycloserine
David Dietrich, Marco J. van Belkum and John C. Vederas
Org. Biomol. Chem., 2012, 10, 2248-2254
DOI: 10.1039/C2OB06864H,

One area of research developed in Dr James N. Wilson‘s lab at the University of Miami (Florida, USA) is aimed at elucidating the complex molecular mechanisms of intercellular communication, via the development of fluorescent analogues of neuroactive compounds.

In their latest OBC communication,  Wilson et al. describe the synthesis, characterization and interaction of cell lines with novel dimeric stilbazolium-based dyes that probe the functional limit of norepinephrine transport (NET) in cells. Upon exposure to different NET proteins, these environmentally sensitive dyes turn on the fluorescence and their binding to NET can be monitored using fluorescence microscopy

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Probing the functional limits of the norepinephrine transporter with self-reporting, fluorescent stilbazolium dimers
Erika L. Smith, Adrienne S. Brown, Edward Adjaye-Mensah and James N. Wilson
Org. Biomol. Chem., 2012, Advance Article
DOI: 10.1039/C2OB06796J, Communication