title: Crystal structure of yeast mitochondrial peripheral membrane protein Tim44p C-terminal domain.
abstract: The protein transports from the cell cytosol to the mitochondria matrix are carried out by the translocase of the outer membrane (TOM) complex and the translocase of the inner membrane (TIM) complexes. Tim44p is an essential mitochondrial peripheral membrane protein and a major component of TIM23 translocon. Tim44p can tightly associate with the inner mitochondrial membrane. To investigate the mechanism by which Tim44p functions in the TIM23 translocon to deliver the mitochondrial protein precursors, we have determined the crystal structure of the yeast Tim44p C-terminal domain to 3.2A resolution using the MAD method. The Tim44p C-terminal domain forms a monomer in the crystal structure and contains six alpha-helices and four antiparallel beta-strands. A large hydrophobic pocket was identified on the Tim44p structure surface. The N-terminal helix A1 is positively charged and the helix A1 protrudes out from the Tim44p main body.
authors.affiliation: Department of Cell Biology, Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, AL 35294-0005, USA.
authors.forename: Ratnakar
authors.initials: R
authors.lastname: Josyula
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Jin
authors.forename: Zhengqing
authors.initials: Z
authors.lastname: Fu
authors.forename: Bingdong
authors.initials: B
authors.lastname: Sha
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry; D003460:Crystallization; D018360:Crystallography, X-Ray; D008565:Membrane Proteins / Q000737:chemistry; D033681:Mitochondrial Membrane Transport Proteins / Q000737:chemistry*; D051336:Mitochondrial Membranes / Q000737:chemistry*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000737:chemistry; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; C077016:TIM44 protein, S cerevisiae; C489671:TIMM44 protein, human