Affiliation:
1. Department of Physiology, Johns Hopkins University Medical School, Baltimore, MD 21205.
Abstract
Studies of two different bacterial anion exchange proteins (antiporters) led us to conclude that both reductionist and integrative approaches contribute to progress in understanding membrane biology. We have used a reductionist perspective in applying cysteine scanning mutagenesis to probe individual amino acid positions of UhpT (uptake of hexose phosphate transporter), the carrier responsible for transport of glucose 6-phosphate by Escherichia coli. This work has established experimental criteria that should allow one to identify and localize the translocation pathway in such membrane proteins. An integrative view is exemplified by work with OxlT (oxalate transporter), the carrier used by an anaerobe Oxalobacter formigenes to catalyze the antiport of divalent oxalate and monovalent formate. The activity of OxlT is functionally coordinated with that of a cytosolic oxalyl decarboxylase; together, these vectorial and scalar activities constitute a metabolic proton pump, allowing O. formigenes to display decarboxylative phosphorylation. The role played by OxlT argues that membrane carriers can assume unanticipated emergent properties when their biochemical functions are properly articulated in relation to other aspects of cell function.
Publisher
The Company of Biologists
Subject
Insect Science,Molecular Biology,Animal Science and Zoology,Aquatic Science,Physiology,Ecology, Evolution, Behavior and Systematics
Cited by
9 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献