An essential amino acid residue in the protein translocation channel revealed by targeted random mutagenesis of SecY.
The SecY/Sec61alpha family of membrane proteins are the central subunits of the putative protein translocation channel. We introduced random mutations into a segment of Escherichia coli SecY within its cytoplasmic domain 5, which was shown previously to be important for the SecA-dependent translocation activity. Mutations were classified into those retaining function and those gaining a dominant-interfering ability caused by a loss of function. These analyses showed that Arg-357, Pro-358, Gly-359, and Thr-362 are functionally important; Arg-357, conserved in almost all organisms, was identified as an indispensable residue.
Mori
H
H
Institute for Virus Research, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan.
Ito
K
K
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics*; D000818:Animals; D001120:Arginine / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005799:Genes, Dominant / Q000235:genetics; D005816:Genetic Complementation Test; D006801:Humans; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D021381:Protein Transport; D000069816:SEC Translocation Channels; D000081416:SecA Proteins; D012694:Serine / Q000235:genetics / Q000378:metabolism; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D021122:Protein Subunits; D000069816:SEC Translocation Channels; C057841:SecY protein, E coli; D014443:Tyrosine; D012694:Serine; D001120:Arginine; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins