title: Second transmembrane segment of FtsH plays a role in its proteolytic activity and homo-oligomerization.
abstract: The FtsH (HflB) protein of Escherichia coli is a membrane-bound ATP-dependent zinc protease. The role(s) of the N-terminal membrane-anchoring region of FtsH were studied by fusion with a maltose-binding protein (MBP) at five different N-termini of FtsH. The MBP-FtsH fusions were expressed in the cytoplasm of E. coli, and were purified as soluble proteins. The four longer constructs, which have a second transmembrane segment and the C-terminal cytoplasmic region in common, retained ATP-dependent protease activity toward heat-shock transcription factor sigma(32), and were found to be homo-oligomers. In contrast, the shortest construct which has the C-terminal cytoplasmic region but not the second transmembrane segment showed neither protease activity nor oligomerization. Therefore, the second transmembrane segment, which neighbors the C-terminal cytoplasmic region of the FtsH, participates in not only its membrane-anchoring, but also its protease activity and homo-oligomerization.
authors.affiliation: Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan.smakino@nibh.go.jp
authors.forename: S
authors.initials: S
authors.lastname: Makino
authors.forename: T
authors.initials: T
authors.lastname: Makino
authors.forename: K
authors.initials: K
authors.lastname: Abe
authors.forename: J
authors.initials: J
authors.lastname: Hashimoto
authors.forename: T
authors.initials: T
authors.lastname: Tatsuta
authors.forename: M
authors.initials: M
authors.lastname: Kitagawa
authors.forename: H
authors.initials: H
authors.lastname: Mori
authors.forename: T
authors.initials: T
authors.lastname: Ogura
authors.forename: T
authors.initials: T
authors.lastname: Fujii
authors.forename: S
authors.initials: S
authors.lastname: Fushinobu
authors.forename: T
authors.initials: T
authors.lastname: Wakagi
authors.forename: H
authors.initials: H
authors.lastname: Matsuzawa
authors.forename: T
authors.initials: T
authors.lastname: Makinoa
mesh_terms: D018528:ATP-Binding Cassette Transporters; D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism; D020816:Amino Acid Motifs / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D003001:Cloning, Molecular; D029968:Escherichia coli Proteins; D006639:Histidine / Q000235:genetics; D006868:Hydrolysis; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009004:Monosaccharide Transport Proteins; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010447:Peptide Hydrolases / Q000378:metabolism*; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification; D014461:Ultracentrifugation
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; C461599:maltose transport system, E coli; D006639:Histidine; D010447:Peptide Hydrolases; D049069:ATP-Dependent Proteases; C513383:FtsH protein, E coli; D000251:Adenosine Triphosphatases