A single Gly114Arg mutation stabilizes the hexameric subunit assembly and changes the substrate specificity of halo-archaeal nucleoside diphosphate kinase.
Nucleoside diphosphate kinase from extremely halophilic archaeon (HsNDK) requires above 2M NaCl concentration for in vitro refolding. Here an attempt was made to isolate mutations that allow HsNDK to refold in low salt media. Such a screening resulted in isolation of an HsNDK mutant, Gly114Arg, which efficiently refolded in the presence of 1M NaCl. This mutant, unlike the wild type enzyme, was expressed in Escherichia coli as an active form. The residue 114 is in close proximity to Glu155 of the neighboring subunit in the three dimensional hexameric structure of the HsNDK. It is thus possible that the attractive electrostatic interactions occur between Arg114 and Glu155 in the mutant HsNDK, stabilizing the hexameric subunit assembly.
Ishibashi
Matsujiro
M
Applied and Molecular Microbiology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
Tatsuda
Shuhei
S
Izutsu
Ken-ichi
K
Kumeda
Kouko
K
Arakawa
Tsutomu
T
Tokunaga
Masao
M
D019943:Amino Acid Substitution; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics; D020134:Catalytic Domain / Q000235:genetics; D019617:Halobacterium salinarum / Q000201:enzymology* / Q000235:genetics; D020125:Mutation, Missense; D009701:Nucleoside-Diphosphate Kinase / Q000737:chemistry* / Q000235:genetics; D017510:Protein Folding; D012965:Sodium Chloride / Q000737:chemistry; D013379:Substrate Specificity / Q000235:genetics
D019843:Archaeal Proteins; D012965:Sodium Chloride; D009701:Nucleoside-Diphosphate Kinase