Functional implications related to the gene structure of the elongation factor EF-Tu from Halobacterium marismortui

• Published in: Nucleic acids research Vol. 18; no. 3; pp. 507 - 511
• Main Authors: BALDACCI, G, GUINET, F, TILLIT, J, ZACCZAI, G, DE RECONDO, A.-M
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 11-02-1990
• Subjects: Amino Acid Sequence; Amino Acids - analysis; Base Composition; Biological and medical sciences; Cloning, Molecular; DNA Restriction Enzymes; DNA, Bacterial - genetics; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; genes; Genes. Genome; Halobacterium; Halobacterium - genetics; Halobacterium marismortui; Macromolecular Substances; Methanococcus; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Nucleic Acid Hybridization; Peptide Elongation Factor Tu - genetics; Protein Conformation; Sequence Homology, Nucleic Acid; Eucaryote; Archaeobacteria; Tertiary structure; Bacteria; Halobacterium; Homology; Primary structure; Halobacteriaceae; Comparative study; Elongation factor EFTu
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/18.3.507

The primary structure of the gene for the elongation factor EF-Tu from the halophilic archaebacterium Halobacterium marismortui (hEF-Tu) is described. It is the first gene of a halophilic elongation factor EF-Tu to be sequenced. When the sequence of hEF-Tu is compared to that of homologous proteins from other organisms, the highest identity (61%) is found with EF-Tu from Methanococcus vannielii, a non-halophilic archaebacterium. In the search for halophilic characteristics therefore the most appropriate comparison is with the M. vannielii sequence. The excess of acidic amino acid residues in the hEF-Tu sequence (already observed in the composition of other halophilic proteins) results to a large extent from changes of Lys, Asn or Gln to Asp or Glu. A structural analysis algorithm applied to the halophilic sequence places these acidic residues on the surface of the protein. The corresponding residues in the crystal structure of the first domain of EF-Tu from E. coli (the only EF-Tu structure available) are grouped in patches on the protein surface, in each of which several residues that may be far apart in the sequence come quite close to each other in the tertiary structure.