Allosteric Inhibition of PTP1B Activity by Selective Modification of a Non-Active Site Cysteine Residue

详细信息    查看全文

• 作者：Stig K. Hansen ; Mark T. Cancilla ; Timothy P. Shiau ; Jenny Kung ; Teresa Chen ; and Daniel A. Erlanson
• 刊名：Biochemistry
• 出版年：2005
• 出版时间：May 31, 2005
• 年：2005
• 卷：44
• 期：21
• 页码：7704 - 7712
• 全文大小：379K
• 年卷期：v.44,no.21(May 31, 2005)
• ISSN：1520-4995

文摘

The fluorogenic reagent 4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (ABDF) attenuatesthe functional activity of the protein tyrosine phosphatase PTP1B by reacting selectively with a singlecysteine residue, leaving other cysteines in the protein unmodified. This modification reduces V_max withoutsubstantially affecting substrate binding (K_m), indicative of an allosteric mode of inhibition. Consistentwith this, the cysteine residue modified by ABDF, Cys 121, lies outside the catalytic site but makesinteractions with residues that contact His 214, which has been shown to be important for catalysis. Cys121 is highly conserved among phosphatases, and ABDF also inhibits TC-PTP and LAR. These findingsillustrate that targeting cysteine residues outside catalytic sites may be exploited in allosterically regulatingenzymes. Moreover, these results suggest a new strategy for inhibiting a promising diabetes target.