title: In Vitro Interaction of the Housekeeping SecA1 with the Accessory SecA2 Protein of Mycobacterium tuberculosis.
abstract: The majority of proteins that are secreted across the bacterial cytoplasmic membrane leave the cell via the Sec pathway, which in its minimal form consists of the dimeric ATP-driven motor protein SecA that associates with the protein-conducting membrane pore SecYEG. Some Gram-positive bacteria contain two homologues of SecA, termed SecA1 and SecA2. SecA1 is the essential housekeeping protein, whereas SecA2 is not essential but is involved in the translocation of a subset of proteins, including various virulence factors. Some SecA2 containing bacteria also harbor a homologous SecY2 protein that may form a separate translocase. Interestingly, mycobacteria contain only one SecY protein and thus both SecA1 and SecA2 are required to interact with SecYEG, either individually or together as a heterodimer. In order to address whether SecA1 and SecA2 cooperate during secretion of SecA2 dependent proteins, we examined the oligomeric state of SecA1 and SecA2 of Mycobacterium tuberculosis and their interactions with SecA2 and the cognate SecA1, respectively. We conclude that both SecA1 and SecA2 individually form homodimers in solution but when both proteins are present simultaneously, they form dissociable heterodimers.
authors.affiliation: Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, Nijenborgh 7, 9727 AG Groningen, The Netherlands.
authors.forename: Irfan
authors.initials: I
authors.lastname: Prabudiansyah
authors.affiliation: Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, Nijenborgh 7, 9727 AG Groningen, The Netherlands.
authors.forename: Ilja
authors.initials: I
authors.lastname: Kusters
authors.affiliation: Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, Nijenborgh 7, 9727 AG Groningen, The Netherlands.
authors.forename: Arnold J M
authors.initials: AJ
authors.lastname: Driessen
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D020043:Genes, Essential; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D021381:Protein Transport; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012996:Solutions; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D011994:Recombinant Proteins; D012996:Solutions; D037521:Virulence Factors; D000251:Adenosine Triphosphatases; C442122:SecA1 protein, Mycobacterium tuberculosis; C442123:SecA2 protein, Mycobacterium