TonB-dependent receptors-structural perspectives - PubMed (original) (raw)

Review

. 2002 Oct 11;1565(2):318-32.

doi: 10.1016/s0005-2736(02)00578-3.

Affiliations

Free article

Review

TonB-dependent receptors-structural perspectives

Andrew D Ferguson et al. Biochim Biophys Acta. 2002.

Free article

Abstract

Plants, bacteria, fungi, and yeast utilize organic iron chelators (siderophores) to establish commensal and pathogenic relationships with hosts and to survive as free-living organisms. In Gram-negative bacteria, transport of siderophores into the periplasm is mediated by TonB-dependent receptors. A complex of three membrane-spanning proteins TonB, ExbB and ExbD couples the chemiosmotic potential of the cytoplasmic membrane with siderophore uptake across the outer membrane. The crystallographic structures of two TonB-dependent receptors (FhuA and FepA) have recently been determined. These outer membrane transporters show a novel fold consisting of two domains. A 22-stranded antiparallel beta-barrel traverses the outer membrane and adjacent beta-strands are connected by extracellular loops and periplasmic turns. Located inside the beta-barrel is the plug domain, composed primarily of a mixed four-stranded beta-sheet and a series of interspersed alpha-helices. Siderophore binding induces distinct local and allosteric transitions that establish the structural basis of signal transduction across the outer membrane and suggest a transport mechanism.

PubMed Disclaimer

Publication types

MeSH terms

Substances

LinkOut - more resources