Format

Send to

Choose Destination
See comment in PubMed Commons below
EMBO J. 2002 May 15;21(10):2312-22.

A novel mode of sensory transduction in archaea: binding protein-mediated chemotaxis towards osmoprotectants and amino acids.

Author information

1
Max-Planck Institut für Biochemie, D-82152 Martinsried, Germany.

Abstract

Directly upstream of the Halobacterium salinarum transducer genes basT and htpIV we identified two open reading frames (orfs) with significant homologies to genes encoding binding proteins for amino acids and compatible solutes, respectively. Behavioral testing of deletion mutants indicates that halobacterial chemotaxis towards branched-chain amino acids as well as compatible osmolytes of the betaine family requires both a binding and a transducer protein. We therefore named the binding/transducer proteins BasB/BasT for branched-chain and sulfur-containing amino acids and CosB/CosT for compatible solutes. Our data support a signaling mechanism with the binding proteins functioning as lipid-anchored receptors interacting with the extracellular domain of their cognate transducers. Inspection of the halobacterial genome suggests that BasB and CosB exclusively mediate chemotaxis responses without any additional role in transport, which is in contrast to bacterial binding proteins, which are always part of ABC transport systems. The CosB/CosT system is the first instance of a chemotaxis signaling pathway for organic osmolytes in the living world and natural abundance 13C-NMR analysis of cytoplasmic extracts suggests that H.salinarum utilizes these solutes for osmotic adaptation.

PMID:
12006484
PMCID:
PMC125379
DOI:
10.1093/emboj/21.10.2312
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center