A cluster of charged and aromatic residues in the C-terminal portion of maltoporin participates in sugar binding and uptake.

A cluster of charged and aromatic residues in the C-terminal portion of maltoporin participates in sugar binding and uptake. Research Abstract Details 

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A cluster of charged and aromatic residues in the C-terminal portion of maltoporin participates in sugar binding and uptake. Abstract Text:

A Charbit,J Wang,V Michel,M Hofnung,

The maltoporin LamB of Escherichia coli K12 is a trimeric protein which facilitates the diffusion of maltose and maltodextrins through the bacterial outer membrane, and also acts as a non-specific porin for small hydrophilic molecules as well as a receptor for phages. Loop L9 (residues 375 to 405) is the most distal and largest surface-exposed loop of LamB. It comprises a central portion, which varies in size and sequence in the maltoporins of known sequence, flanked by two conserved regions containing charged and aromatic residues. In order to identify the residues within the proximal region that are specifically involved in sugar utilization, we used site-directed mutagenesis to change, individually, each of the charged (five) and aromatic (three) residues in the region 371 to 379 into alanine. None of the eight single amino acid substitutions affected the phage receptor activity of LamB. In contrast, they all affected, to variable extents, maltoporin functions. For all the mutants, very good correlations were observed between the effects on sugar binding and on in vivo uptake. In no case were maltoporin functions completely abolished. Mutants E374 A and W376 A were the most impaired (with over 60% reduction in dextrin binding and in vivo uptake of maltose and maltopentaose). These two mutations also led to an increased bacterial sensitivity to bacitracin and vancomycin. The functional and structural implications are discussed.

A cluster of charged and aromatic residues in the C-terminal portion of maltoporin participates in sugar binding and uptake. Publishing Authors By Initials

A Charbit,J Wang,V Michel,M Hofnung,

For similar carbohydrates: glycoconjugates: glycopeptides: vancomycin research abstracts see: carbohydrates: glycoconjugates: glycopeptides: vancomycin research

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A cluster of charged and aromatic residues in the C-terminal portion of maltoporin participates in sugar binding and uptake. Journal Published:

PUBLICATION TYPE: Research Support, Non-U.S. Gov

Journal: Molecular & general genetics : MGG

VOLUME: 260

Page Numbers: 185-92

Journal Abbreviation: Mol. Gen. Genet.

ISSN: 0026-8925

DAY: 27

MONTH: Nov

YEAR: 1998

A cluster of charged and aromatic residues in the C-terminal portion of maltoporin participates in sugar binding and uptake. Information

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LANGUAGE: eng

NlmUniqueID: 125036

A cluster of charged and aromatic residues in the C-terminal portion of maltoporin participates in sugar binding and uptake. Keywords Mesh Terms:

KEYWORDS: Vancomycin

MESH TERMS: pharmacology

Chemical & Substance for Abstract: A cluster of charged and aromatic residues in the C-terminal portion of maltoporin participates in sugar binding and uptake. Information

Substance Name: maltodextrin

Registry Number: 9050-36-6

Grant and Affiliation Information for A cluster of charged and aromatic residues in the C-terminal portion of maltoporin participates in sugar binding and uptake.

AFFILIATION: Unité de Programmation Moléculaire et Toxicologie Génétique, CNRS URA1444, Istitut Pasteur, Paris, France. acharbit@pasteur.fr

Country: GERMANY

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MEDLINETA: Mol Gen Genet

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