Premium
Two distinct ATP‐binding domains are needed to promote protein export by Escherichia coli SecA ATPase
Author(s) -
Mitchell Christine,
Oliver Donald
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.tb00921.x
Subject(s) - biology , biochemistry , atpase , chromosomal translocation , binding domain , binding site , mutagenesis , escherichia coli , nucleotide , plasma protein binding , amino acid , oligonucleotide , walker motifs , binding protein , gene , mutation , enzyme , atp hydrolysis
Summary Six putative ATP‐binding motifs of SecA protein were altered by oligonucleotide‐directed mutagenesis to try to define the ATP‐binding regions of this multifunctional protein. The effects of the mutations were analysed by genetic and biochemical assays. The results show that SecA contains two essential ATP‐binding domains. One domain is responsible for high‐affinity ATP binding and contains motifs AO and BO, located at amino acid residues 102‐109 and 198‐210, respectively. A second domain is responsible for low‐affinity ATP binding and contains motifs A3 and a predicted B motif located at amino acid residues 503‐511 and 631‐653, respectively. The ATP‐binding properties of both domains were essential for SecA‐dependent translocation ATPase and in vitro protein translocation activities. The significance of these findings for the mechanism of SecA‐dependent protein translocation is discussed.