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SyrD is required for syringomycin production by Pseudomonas syringae pathovar syringae and is related to a family of ATP‐binding secretion proteins
Author(s) -
Quigley Neil B.,
Mo YinYuan,
Gross Dennis C.
Publication year - 1993
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1993.tb01738.x
Subject(s) - pseudomonas syringae , biology , atp binding cassette transporter , pathovar , mutant , secretion , open reading frame , gene , biochemistry , virulence , homology (biology) , genetics , peptide sequence , microbiology and biotechnology , pseudomonas , pseudomonadaceae , transporter , bacteria
Summary The syrD gene of Pseudomonas syringae pathovar syringae strain B301D‐R was characterized and sequenced. The syrD open reading frame is 1695bp long and encodes a predicted protein, SyrD, of =63kDa. Database searches revealed that SyrD shares a high degree of similarity with the ATP‐binding cassette (ABC) superfamily of transporter proteins which are responsible for specific nutrient uptake and for secretion of certain cellular products in prokaryotes, and for multiple drug resistance in mammals. The amino acid sequence homology between SyrD and the ABC proteins was greatest at the conserved residues which constitute the ATP‐binding cassette of these proteins; these residues lie in the hydrophilic C‐terminal half of SyrD. The N ‐terminus of SyrD is predicted to be hydrophobic and to contain six membrane‐spanning α‐helices. syrD mutants of strain B301D‐R were significantly less virulent than other syr mutants, were deficient in four large polypeptides thought to be components of a syringomycin synthetase complex, and showed reduced expression of a syrB‐lacZ reporter gene fusion in trans. It is proposed that SyrD is a cyto‐plasmic membrane protein that functions as an ATP‐driven efflux pump for the secretion of syringomycin.