The high affinity ATP binding site modulates the SecA–precursor interaction

FEBS Letters

de Kruijff, Ben¹  van Voorst, Frank¹  Vereyken, Ingrid J¹ 

[1] CBLE, Institute of Biomembranes, Department of Biochemistry of Membranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands

关键词: Phospholipid;    Protein translocation;    Signal sequence;    Crosslinking;    SecA;    NBD;    nucleotide binding domain;    APDP;    N-[4-(p-azidosalicylamido)butyl]-3′-(2′-pyridyldithio)propionamide;    AMP-PNP;    5-adenylylimidodiphosphate;    DTNB;    5;    5′-dithio-bis(2-nitrobenzoic acid);    TCA;    trichloroacetic acid;    DMSO;    dimethylsulfoxide;    PBS;    phosphate-buffered saline;    SDS–PAGE;    sodium dodecyl sulfate–polyacrylamide gel electrophoresis;   

DOI  :  10.1016/S0014-5793(00)02209-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

SecA is the central component of the protein-translocation machinery of Escherichia coli. It is able to interact with the precursor protein, the chaperone SecB, the integral membrane protein complex SecYEG, acidic phospholipids and its own mRNA. We studied the interaction between prePhoE and SecA by using a site-specific photocrosslinking strategy. We found that SecA is able to interact with both the signal sequence and the mature domain of prePhoE. Furthermore, this interaction was dependent on the type of nucleotide bound. SecA in the ADP-bound conformation was unable to crosslink with the precursor, whereas the ATP-bound conformation was active in precursor crosslinking. The SecA–precursor interaction was maintained in the presence of E. coli phospholipids but was loosened by the presence of phosphatidylglycerol bilayers. Examining SecA ATP binding site mutants demonstrated that ATP hydrolysis at the N-terminal high affinity binding site is responsible for the changed interaction with the preprotein.

【 授权许可】

Unknown