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Photoaffinity Labeling (photoaffinity + labeling)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Atrial natriuretic peptide-dependent photolabeling of a regulatory ATP-binding site on the natriuretic peptide receptor-A

FEBS JOURNAL, Issue 21 2005
Simon Joubert
The natriuretic peptide receptor-A (NPR-A) is composed of an extracellular ligand-binding domain, a transmembrane-spanning domain, a kinase homology domain (KHD) and a guanylyl cyclase domain. Because the presence of ATP or adenylylimidodiphosphate reduces atrial natriuretic peptide (ANP) binding and is required for maximal guanylyl cyclase activity, a direct interaction of ATP with the receptor KHD domain is plausible. Therefore, we investigated whether ATP interacts directly with a binding site on the receptor by analyzing the binding of a photoaffinity analog of ATP to membranes from human embryonic kidney 293 cells expressing the NPR-A receptor lacking the guanylyl cyclase moiety (,GC). We demonstrate that this receptor (NPR-A-,GC) can be directly labeled by 8-azido-3,-biotinyl-ATP and that labeling is highly increased following ANP treatment. The mutant receptor ,KC, which does not contain the KHD, is not labeled. Photoaffinity labeling of the NPR-A-,GC is reduced by 50% in the presence of 550 µm ATP, and competition curve fitting studies indicate a Hill slope of 2.2, suggestive of cooperative binding. This approach demonstrates directly that the interaction of ANP with its receptor modulates the binding of ATP to the KHD, probably through a conformational change in the KHD. In turn, this conformational change is essential for maximal activity. In addition, the ATP analog, 8-azido-adenylylimidodiphosphate, inhibits guanylyl cyclase activity but increases ANP binding to the extracellular domain. These results suggest that the KHD regulates ANP binding and guanylyl cyclase activity independently. [source]

Synthesis of Cluster Mannosides Carrying a Photolabile Diazirine Group

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2006
Mark Walter
Abstract We are investigating the mechanisms underlying the carbohydrate-specific adhesion of bacteria such as Escherichia coli to the glycocalyx of their potential host cells. E. coli possess protein appendages, which are called type 1 fimbriae. Part of type 1 fimbriae is a protein named FimH, which is a mannose-specific lectin. We wish to use photoaffinity labeling to elucidate mannose binding sites on FimH. Thus we report the synthesis of di- and trivalent cluster mannosides, which carry a photolabile diazirine group. The diazirine group was introduced by a convergent approach using thiourea bridging (products 6, 13, 17, and 27) or in a divergent synthesis leading to the divalent cluster mannoside 31. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Biological significance and development of practical synthesis of biotin

MEDICINAL RESEARCH REVIEWS, Issue 4 2006
Masahiko Seki
Abstract Biotin (1), a water-soluble B series vitamin, distributes widely in microorganisms, plants, and animals. Biosynthesis of 1 involves five steps sequence starting from pimelic acid. The last step, a transformation from dethiobiotin (DTB) to 1, includes an iron clusters-mediated radical process. The compound 1 is a cofactor of carboxylation enzymes and plays crucial roles in the metabolism of fatty acids, sugars, and ,-amino acids. In addition to the increasing application to feed additives, recent reports have revealed that 1 enhances insulin secretion in animals, suggesting it for a promising therapeutic candidate for an anti-diabetes drug. The remarkably strong affinity of 1 with avidin and streptavidin has been extensively applied for such technologies as photoaffinity labeling. Among the number of approaches to 1 so far developed in 50 years, a synthesis using L -cysteine and thiolactone as a starting material and a key intermediate, respectively, represents one of the best routes leading to 1, because of short steps, high yield, use of inexpensive reagents, and ease of operation. © 2006 Wiley Periodicals, Inc. Med Res Rev, 26, No. 4, 434,482, 2006 [source]

Investigation of Protein,Ligand Interactions by Mass Spectrometry

CHEMMEDCHEM, Issue 4 2007
Andrea Sinz Prof.
Abstract The rate of drug discovery is greatly dependent on the development and improvement of rapid and reliable analytical methods that allow screening for protein,ligand interactions. The solution-based methods for investigating protein,ligand interactions by mass spectrometry (MS), which are discussed in this paper, are hydrogen/deuterium exchange of protein backbone amide hydrogens, and photoaffinity labeling. Moreover, MS analysis of intact noncovalent protein,ligand complexes is described. Fourier transform ion cyclotron resonance mass spectrometry (FTICR,MS) with its ultra-high resolution and excellent mass accuracy is also considered herein as it is gaining increasing popularity for a mass spectrometric investigation of protein,ligand interactions. [source]