Extensive homology between membrane-associated components of histidine and maltose transport systems of Salmonella typhimurium and Escherichia coli.

E Gilson,C F Higgins,M Hofnung,G Ferro-Luzzi Ames,H Nikaido

doi:10.1016/s0021-9258(18)33962-0

Abstract

A strong homology was found between the amino acid sequences, deduced from DNA nucleotide sequences, of cytoplasmic membrane-associated components of the high affinity histidine transport system of Salmonella typhimurium (coded by the hisP gene) and the maltose-maltodextrin transport system of Escherichia coli (coded by the malK gene). When the HisP protein sequence was aligned with that of the NH2-terminal two-thirds of the MalK protein, 32% of the positions were identical, and an additional 35% were occupied by functionally similar amino acid residues. These results suggest that some, and possibly many, "periplasmic-binding protein-dependent" transport systems have evolved from a common ancestral system.

Highlights

A significantsequence homology has been reported between periplasmic binding proteins involved in thetransport of solutes with some shared properties. ( a )An extensive homology was found between the histidine- and the lysine-arginine
A stronghomology was found between theamino these two proteins ( h i d and argT, respectively) clearly indiacidsequencesd, educed from DNA nucleotide se- cated that thegenes had originated by tandem duplication of quences, of cytoplasmic membrane-associated compo- an ancestral gene [18]. [15]An extensive homology has nents of the high affinity histidine transportsystem of been reported between the leucine-isoleucine-valine-and the Salmonella typhimurium and leucine-specific-bindingproteins [19]. (c) A minor homology the maltose-maltodextrin transport system of Esche- was reported between the arabinose, galactose, and riboserichia coli
These results suggest that some, and possibly many, binding proteins of E. coli [20]

Summary

Introduction

A significantsequence homology has been reported between periplasmic binding proteins involved in thetransport of solutes with some shared properties. ( a )An extensive homology was found between the histidine- and the lysine-arginine-. Protein sequence was aligned with that of the N H z terminal two-thirds of the MalK protein, 32% of the positions were identical, and an additional 35% were occupied by functionally similar amino acid residues.

Results

Conclusion