Effects of N-terminal deletion mutation on arginine kinase from the sea cucumber Stichopus japonicus.
Deletion mutants of arginine kinase (AK) were constructed: AKND4, AKND6, AKND8, AKND10 (the first 4, 6, 8 and 10 amino acids of the N-terminal were deleted), to investigate the structural and functional roles of the N-terminal. Results showed that the deletion mutants assume less compact conformations compared to the wild-type, whereas no significant changes of the secondary or the quaternary structures were observed, implying that the deletions cause a perturbation in the tertiary structure or the hydrodynamic properties of the enzyme. The enzymatic and denaturing measurements showed that removal of the N-terminal residues decreased the activity and stability of the enzyme markedly. The instability increased in accord with the increased number of amino acid residues removed from the N-terminal of AK. It can be concluded that the N-terminal of AK plays an important role in maintaining the conformational stability and catalytic function of the enzyme.
Liu
Tao-Tao
TT
Department of Biological Science and Biotechnology, Tsinghua University, Beijing 100084, China.
Wang
Xi-Cheng
XC
D000595:Amino Acid Sequence; D000818:Animals; D001122:Arginine Kinase / Q000737:chemistry* / Q000235:genetics; D002942:Circular Dichroism; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009154:Mutation; D017510:Protein Folding; D020673:Protein Renaturation; D020836:Protein Structure, Quaternary / Q000235:genetics; D017384:Sequence Deletion; D013050:Spectrometry, Fluorescence; D047528:Stichopus / Q000201:enzymology*
D001122:Arginine Kinase