Nucleotide sequence of the Escherichia coli motB gene and site-limited incorporation of its product into the cytoplasmic membrane.
AUTOR(ES)
Stader, J
RESUMO
The motB gene product of Escherichia coli is an integral membrane protein required for rotation of the flagellar motor. We have determined the nucleotide sequence of the motB region and find that it contains an open reading frame of 924 nucleotides which we ascribe to the motB gene. The predicted amino acid sequence of the gene product is 308 residues long and indicates an amphipathic protein with one major hydrophobic region, about 22 residues long, near the N terminus. There is no consensus signal sequence. We postulate that the protein has a short N-terminal region in the cytoplasm, an anchoring region in the membrane consisting of two spanning segments, and a large cytoplasmic C-terminal domain. By placing motB under control of the tryptophan operon promoter of Serratia marcescens, we have succeeded in overproducing the MotB protein. Under these conditions, the majority of MotB was found in the cytoplasm, indicating that the membrane has a limited capacity to incorporate the protein. We conclude that insertion of MotB into the membrane requires the presence of other more hydrophobic components, possibly including the MotA protein or other components of the flagellar motor. The results further reinforce the concept that the total flagellar motor consists of more than just the basal body.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=214583Documentos Relacionados
- Mutant MotB proteins in Escherichia coli.
- Co-overproduction and localization of the Escherichia coli motility proteins motA and motB.
- Rhodobacter sphaeroides WS8 expresses a polypeptide that is similar to MotB of Escherichia coli.
- Evidence for interactions between MotA and MotB, torque-generating elements of the flagellar motor of Escherichia coli.
- Function of Protonatable Residues in the Flagellar Motor of Escherichia coli: a Critical Role for Asp 32 of MotB