Universität zu Köln

Ziegler, Christine, Bremer, Erhard and Kraemer, Reinhard (2010). The BCCT family of carriers: from physiology to crystal structure. Mol. Microbiol., 78 (1). S. 13 - 35. HOBOKEN: WILEY. ISSN 1365-2958

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Abstract

P>Increases in the environmental osmolarity are key determinants for the growth of microorganisms. To ensure a physiologically acceptable level of cellular hydration and turgor at high osmolarity, many bacteria accumulate compatible solutes. Osmotically controlled uptake systems allow the scavenging of these compounds from scarce environmental sources as effective osmoprotectants. A number of these systems belong to the BCCT family (betaine-choline-carnitine-transporter), sodium- or proton-coupled transporters (e.g. BetP and BetT respectively) that are ubiquitous in microorganisms. The BCCT family also contains CaiT, an l-carnitine/gamma-butyrobetaine antiporter that is not involved in osmotic stress responses. The glycine betaine transporter BetP from Corynebacterium glutamicum is a representative for osmoregulated symporters of the BCCT family and functions both as an osmosensor and osmoregulator. The crystal structure of BetP in an occluded conformation in complex with its substrate glycine betaine and two crystal structures of CaiT in an inward-facing open conformation in complex with l-carnitine and gamma-butyrobetaine were reported recently. These structures and the wealth of biochemical data on the activity control of BetP in response to osmotic stress enable a correlation between the sensing of osmotic stress by a transporter protein with the ensuing regulation of transport activity. Molecular determinants governing the high-affinity binding of the compatible solutes by BetP and CaiT, the coupling in symporters and antiporters, and the osmoregulatory properties are discussed in detail for BetP and various BCCT carriers.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ziegler, Christine UNSPECIFIED UNSPECIFIED UNSPECIFIED Bremer, Erhard UNSPECIFIED UNSPECIFIED UNSPECIFIED Kraemer, Reinhard UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-495985
DOI:	10.1111/j.1365-2958.2010.07332.x
Journal or Publication Title:	Mol. Microbiol.
Volume:	78
Number:	1
Page Range:	S. 13 - 35
Date:	2010
Publisher:	WILEY
Place of Publication:	HOBOKEN
ISSN:	1365-2958
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language GLYCINE BETAINE TRANSPORT; COMPATIBLE SOLUTE HYDROXYECTOINE; BINDING PROTEIN OPUAC; ESCHERICHIA-COLI; CORYNEBACTERIUM-GLUTAMICUM; CHOLINE TRANSPORTER; BACILLUS-SUBTILIS; LIGAND-BINDING; UPTAKE SYSTEM; SINORHIZOBIUM-MELILOTI Multiple languages Biochemistry & Molecular Biology; Microbiology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/49598