Fine Structure-Funtional Anaiysis of Catalytic and Conserved Amino Acids of Neuraminidase Gene, nanH, of Clostridium Perfringens

10.30047/JGMB.199412.0012

Chin-Hsiang Chien；Yih-Jyh Shann

Journal of Genetics and Molecular Biology

5卷4期（1994 / 12 / 01）

81 - 81

英文

The nanH gene encoding the neuraminidase from C. perfringens ATCC 10543 was cloned in JM109 using pUC19 as a vector. Sequence analysis revealed an ORF, nt 310-1455, encoding 382 amino acids; that is proceeded by a typical Shine-Dalgarno sequences, GGAGGAGA,and without signal peptide sequence. Four regions of amino acid sequence 71 to 82, 140 to 151, 208 to 219, and 155 to 266 constituted four repeated and conserved sequence motif –Ser-X-Asp-X-Gly-Thr-Trp-, “Asp boxes”. The homology-modeled structure of C. perfringens nanH showed the same fold topology as that of X-ray three dimensional structure of nanH of Salmonella tyhimurium LT12. Amino acid residues Arg37, Arg56, Asp62, His63, Asp100, Glu230, Asp247, Tyr347 and Glu362 located around the pocket of modeled C. perfringens nanH, are superimposed with the active site pocket of S. typhimurium LT12, nanH, of which the catalytic amino acid residues have not been determined. Asp100 and Asp62 are found to be involved in the catalytic activity of C. perfringens nanH as analyzed by site-directed mutagenesis and immunoreactive properties. Four “Asp boxes” motifs are found to be remote from the active site pocket. Mutational and immunoreactive analysis of highly conserved amino acids located in the “Asp boxes” indicated that these highly conserved residues are involved in the folding or transport of nanH.