Redox regulation of protein tyrosine phosphatase 1B (PTP1B): Importance of steric and electronic effects on the unusual cyclization of the sulfenic acid intermediate to a sulfenyl amide

Sarma, Bani Kanta (2013) Redox regulation of protein tyrosine phosphatase 1B (PTP1B): Importance of steric and electronic effects on the unusual cyclization of the sulfenic acid intermediate to a sulfenyl amide. In: Journal of Molecular Structure, 1048 . pp. 410-419.

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Abstract

The redox regulation of protein tyrosine phosphatase 1B (PTP1B) via the unusual transformation of its sulfenic acid (PTP1B-SOH) to a cyclic sulfenyl amide intermediate is studied by using small molecule chemical models. These studies suggest that the sulfenic acids derived from the H2O2-mediated reactions o-amido thiophenols do not efficiently cyclize to sulfenyl amides and the sulfenic acids produced in situ can be trapped by using methyl iodide. Theoretical calculations suggest that the most stable conformer of such sulfenic acids are stabilized by n(O) -> sigma* (S-OH) orbital interactions, which force the -OH group to adopt a position trans to the S center dot center dot center dot O interaction, leading to an almost linear arrangement of the O center dot center dot center dot S-O moiety and this may be the reason for the slow cyclization of such sulfenic acids to their corresponding sulfenyl amides. On the other hand, additional substituents at the 6-position of o-amido phenylsulfenic acids that can induce steric environment and alter the electronic properties around the sulfenic acid moiety by S center dot center dot center dot N or S center dot center dot center dot O nonbonded interactions destabilize the sulfenic acids by inducing strain in the molecule. This may lead to efficient the cyclization of such sulfenic acids. This model study suggests that the amino acid residues in the close proximity of the sulfenic acid moiety in PTP1B may play an important role in the cyclization of PTP1B-SOH to produce the corresponding sulfenyl amide.

Item Type:	Journal Article
Publication:	Journal of Molecular Structure
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	AIM Analysis; DFT Calculations; NBO Analysis; Redox Regulation; Sulfenic Acid; Sufenyl Amide
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	24 Sep 2013 06:25
Last Modified:	24 Sep 2013 06:25
URI:	http://eprints.iisc.ac.in/id/eprint/47419

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