2jbu

From Proteopedia

Revision as of 17:49, 18 December 2007

CRYSTAL STRUCTURE OF HUMAN INSULIN DEGRADING ENZYME COMPLEXED WITH CO-PURIFIED PEPTIDES.

Overview

Insulin-degrading enzyme (IDE) is a zinc metalloprotease that hydrolyzes, amyloid-beta (Abeta) and insulin, which are peptides associated with, Alzheimer disease (AD) and diabetes, respectively. Our previous structural, analysis of substrate-bound human 113-kDa IDE reveals that the N- and, C-terminal domains of IDE, IDE-N and IDE-C, make substantial contact to, form an enclosed catalytic chamber to entrap its substrates. Furthermore, IDE undergoes a switch between the closed and open conformations for, catalysis. Here we report a substrate-free IDE structure in its closed, conformation, revealing the molecular details of the active conformation, of the catalytic site of IDE and new insights as to how the closed, conformation of IDE may be kept in its resting, inactive conformation. We, also show that Abeta is degraded more efficiently by IDE carrying, destabilizing mutations at the interface of IDE-N and IDE-C (D426C and, K899C), resulting in an increase in V(max) with only minimal changes to, K(m). Because ATP is known to activate the ability of IDE to degrade short, peptides, we investigated the interaction between ATP and activating, mutations. We found that these mutations rendered IDE less sensitive to, ATP activation, suggesting that ATP might facilitate the transition from, the closed state to the open conformation. Consistent with this notion, we, found that ATP induced an increase in hydrodynamic radius, a shift in, electrophoretic mobility, and changes in secondary structure. Together, our results highlight the importance of the closed conformation for, regulating the activity of IDE and provide new molecular details that will, facilitate the development of activators and inhibitors of IDE.

About this Structure

2JBU is a Single protein structure of sequence from Escherichia coli and Homo sapiens with DIO as ligand. Active as Insulysin, with EC number 3.4.24.56 Known structural/functional Site: . Full crystallographic information is available from OCA.

Reference

Structure of Substrate-free Human Insulin-degrading Enzyme (IDE) and Biophysical Analysis of ATP-induced Conformational Switch of IDE., Im H, Manolopoulou M, Malito E, Shen Y, Zhao J, Neant-Fery M, Sun CY, Meredith SC, Sisodia SS, Leissring MA, Tang WJ, J Biol Chem. 2007 Aug 31;282(35):25453-63. Epub 2007 Jul 5. PMID:17613531

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