Crystal structure of the bovine mitochondrial elongation factor Tu.Ts complex.
The three-dimensional structure of the bovine mitochondrial elongation factor (EF)-Tu.Ts complex (EF-Tumt.Tsmt) has been determined to 2.2-A resolution using the multi-wavelength anomalous dispersion experimental method. This complex provides the first insight into the structure of EF-Tsmt. EF-Tsmt is similar to Escherichia coli and Thermus thermophilus EF-Ts in the amino-terminal domain. However, the structure of EF-Tsmt deviates considerably in the core domain with a five-stranded beta-sheet forming a portion of subdomain N of the core. In E. coli EF-Ts, this region is composed of a three-stranded sheet. The coiled-coil domain of the E. coli EF-Ts is largely eroded in EF-Tsmt, in which it consists of a large loop packed against subdomain C of the core. The conformation of bovine EF-Tumt in complex with EF-Tsmt is distinct from its conformation in the EF-Tumt.GDP complex. When domain III of bovine EF-Tumt.GDP is superimposed on domain III of EF-Tumt in the EF-Tumt.Tsmt complex, helix B from domain I is also almost superimposed. However, the rest of domain I is rotated relative to this helix toward domain II, which itself is rotated toward domain I relative to domain III. Extensive contacts are observed between the amino-terminal domain of EF-Tsmt and domain I of EF-Tumt. Furthermore, the conserved TDFV sequence of EF-Tsmt also contacts domain I with the side chain of Asp139 contacting helix B of EF-Tumt and inserting the side chain of Phe140 between helices B and C. The structure of the EF-Tumt.Tsmt complex provides new insights into the nucleotide exchange mechanism and provides a framework for explaining much of the mutational data obtained for this complex.
Jeppesen
Mads Gravers
MG
Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10 C, 8000 Aarhus C, Denmark.
Navratil
Tomas
T
Spremulli
Linda Lucy
LL
Nyborg
Jens
J
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray / Q000379:methods; D004926:Escherichia coli / Q000378:metabolism; D006147:Guanine / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010444:Peptide Elongation Factor Tu / Q000737:chemistry*; D010445:Peptide Elongation Factors / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016963:Thermus thermophilus / Q000378:metabolism
D010445:Peptide Elongation Factors; C023512:elongation factor Ts; D006147:Guanine; D010444:Peptide Elongation Factor Tu