Structural studies on the decameric S. typhimurium arginine decarboxylase (ADC): Pyridoxal 5'-phosphate binding induces conformational changes

Deka, G and Bharath, SR and Savithri, HS and Murthy, MRN (2017) Structural studies on the decameric S. typhimurium arginine decarboxylase (ADC): Pyridoxal 5'-phosphate binding induces conformational changes. In: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 490 (4). pp. 1362-1368.

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Abstract

Enteric pathogens such as Salmonella typhimurium colonize the human gut in spite of the lethal acidic pH environment (pH < 2.5) due to the activation of inducible acid tolerance response (ATR) systems. The pyridoxal 5'-phosphate (PLP)-dependent enzyme, biodegradative arginine decarboxylase (ADC, encoded by AdiA), is a component of an ATR system. The enzyme consumes a cytoplasmic proton in the process of arginine degradation to agmatine. Arginine-agmatine antiporter (AdiC) exchanges the product agmatine for arginine. In this manuscript, we describe the structure of Salmonella typhimurium ADC (StADC). The decameric structure assembled from five dimers related by a non crystallographic 5-fold symmetry represents the first apo-form of the enzyme. The structure suggests that PLP-binding is not a prerequisite for oligomerization. Comparison with E. coli ADC reveals that PLP-binding is accompanied by the movement and ordering of two loops (residues 150-159 and 191-197) and a few active site residues such as His256 and Lys257. A number of residues important for substrate binding are disordered in the apo-StADC structure indicating that PLP binding is important for substrate binding. Unlike the interactions between 5-fold related protomers, interactions that stabilize the dimeric structure are not pH dependent. (C) 2017 Elsevier Inc. All rights reserved.

Item Type:	Journal Article
Publication:	BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Additional Information:	Copy right for this article belongs to the ACADEMIC PRESS INC ELSEVIER SCIENCE, 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA
Department/Centre:	Division of Biological Sciences > Biochemistry Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	01 Sep 2017 05:49
Last Modified:	25 Feb 2019 11:13
URI:	http://eprints.iisc.ac.in/id/eprint/57684

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