Site-directed mutagenesis studies of the amino acid residue at position 412 of Escherichia coli TolC which is required for the activity.
The Escherichia coli TolC acts as a channel-tunnel in the transport of molecules across the outer membrane. We previously showed that the region extending from the 50th to the 60th amino acid residues from the carboxy terminus is involved in the transport activity of TolC. To clarify which amino acids are important to the activity, we mutated the gene coding these residues and examined the activity of the mutant TolCs. The results showed that leucine at position 412, the 60th amino acid residue from the carboxy terminal end, is important. Further mutational research on the residue suggested that TolC required a nonpolar amino acid residue at position 412 to express its activity.
Yamanaka
Hiroyasu
H
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro, Tokushima, Tokushima, 770-8514, Japan. yama@ph.bunri-u.ac.jp
Nomura
Tomohiko
T
Morisada
Naoyuki
N
Shinoda
Sumio
S
Okamoto
Keinosuke
K
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003087:Colicins / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009675:Novobiocin / Q000494:pharmacology; D013329:Structure-Activity Relationship
D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D003087:Colicins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C073126:tolC protein, E coli; D009675:Novobiocin