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Title: Kinetic characterization of Vibrio cholerae ApbE: Substrate specificity and regulatory mechanisms

Abstract

ApbE is a member of a novel family of flavin transferases that incorporates flavin mononucleotide (FMN) to subunits of diverse respiratory complexes, which fulfill important homeostatic functions. In this work a detailed characterization of Vibrio cholerae ApbE physiologic activity, substrate specificity and pH dependency was carried out. The data obtained show novel characteristics of the regulation and function of this family. For instance, our experiments indicate that divalent cations are essential for ApbE function, and that the selectivity depends largely on size and the coordination sphere of the cation. Our data also show that ApbE regulation by pH, ADP and potassium is an important mechanism that enhances the adaptation, survival and colonization of V. cholerae in the small intestine. Moreover, studies of the pH-dependency of the activity show that the reaction is favored under alkaline conditions, with a pKa of 8.4. These studies, together with sequence and structure analysis allowed us to identify His257, which is absolutely conserved in the family, as a candidate for the residue whose deprotonation controls the activity. Remarkably, the mutant H257G abolished the flavin transfer activity, strongly indicating that this residue plays an important role in the catalytic mechanism of ApbE.

Authors:
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Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Institutes of Health (NIH)
OSTI Identifier:
1410114
Resource Type:
Journal Article
Resource Relation:
Journal Name: PLoS ONE; Journal Volume: 12; Journal Issue: 10
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES

Citation Formats

Fang, Xuan, Liang, Pingdong, Raba, Daniel Alexander, Rosas-Lemus, Mónica, Chakravarthy, Srinivas, Tuz, Karina, Juárez, Oscar, and Permyakov, Eugene A. Kinetic characterization of Vibrio cholerae ApbE: Substrate specificity and regulatory mechanisms. United States: N. p., 2017. Web. doi:10.1371/journal.pone.0186805.
Fang, Xuan, Liang, Pingdong, Raba, Daniel Alexander, Rosas-Lemus, Mónica, Chakravarthy, Srinivas, Tuz, Karina, Juárez, Oscar, & Permyakov, Eugene A. Kinetic characterization of Vibrio cholerae ApbE: Substrate specificity and regulatory mechanisms. United States. doi:10.1371/journal.pone.0186805.
Fang, Xuan, Liang, Pingdong, Raba, Daniel Alexander, Rosas-Lemus, Mónica, Chakravarthy, Srinivas, Tuz, Karina, Juárez, Oscar, and Permyakov, Eugene A. Tue . "Kinetic characterization of Vibrio cholerae ApbE: Substrate specificity and regulatory mechanisms". United States. doi:10.1371/journal.pone.0186805.
@article{osti_1410114,
title = {Kinetic characterization of Vibrio cholerae ApbE: Substrate specificity and regulatory mechanisms},
author = {Fang, Xuan and Liang, Pingdong and Raba, Daniel Alexander and Rosas-Lemus, Mónica and Chakravarthy, Srinivas and Tuz, Karina and Juárez, Oscar and Permyakov, Eugene A.},
abstractNote = {ApbE is a member of a novel family of flavin transferases that incorporates flavin mononucleotide (FMN) to subunits of diverse respiratory complexes, which fulfill important homeostatic functions. In this work a detailed characterization of Vibrio cholerae ApbE physiologic activity, substrate specificity and pH dependency was carried out. The data obtained show novel characteristics of the regulation and function of this family. For instance, our experiments indicate that divalent cations are essential for ApbE function, and that the selectivity depends largely on size and the coordination sphere of the cation. Our data also show that ApbE regulation by pH, ADP and potassium is an important mechanism that enhances the adaptation, survival and colonization of V. cholerae in the small intestine. Moreover, studies of the pH-dependency of the activity show that the reaction is favored under alkaline conditions, with a pKa of 8.4. These studies, together with sequence and structure analysis allowed us to identify His257, which is absolutely conserved in the family, as a candidate for the residue whose deprotonation controls the activity. Remarkably, the mutant H257G abolished the flavin transfer activity, strongly indicating that this residue plays an important role in the catalytic mechanism of ApbE.},
doi = {10.1371/journal.pone.0186805},
journal = {PLoS ONE},
number = 10,
volume = 12,
place = {United States},
year = {Tue Oct 24 00:00:00 EDT 2017},
month = {Tue Oct 24 00:00:00 EDT 2017}
}