FtsH exists as an exceptionally large complex containing HflKC in the plasma membrane of Escherichia coli.
FtsH is an ATP-dependent and membrane-associated protease, which exerts processive proteolysis against membrane-embedded and soluble substrate proteins. Although previous studies suggested that it functions as a homo-oligomer and it also interacts with HflK-HflC membrane protein complex (HflKC), it is still important to address the question of what kind of supramolecular assembly FtsH forms in wild-type cells. Now we show that FtsH in wild-type Escherichia coli cells exists exclusively as a large complex, termed FtsH holo-enzyme, which can be separated from bulk of membrane proteins after detergent solubilization and velocity sedimentation. This complex appears to have molecular mass of around 1000 kDa. A tentative model is presented that it is composed of hexamers of FtsH and of HflKC, with an ability to bind one or a few substrate molecules.
Saikawa
Naoya
N
Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan.
Akiyama
Yoshinori
Y
Ito
Koreaki
K
D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D002458:Cell Fractionation; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D046911:Macromolecular Substances; D021962:Membrane Microdomains / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D011485:Protein Binding; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D049069:ATP-Dependent Proteases; C513383:FtsH protein, E coli; D000251:Adenosine Triphosphatases