Amino Acid Sequence of Egyptian Goose Egg-White Lysozyme and Effects of Amino Acid Substitution on the Enzymatic Activity

作者：Kawamura Shunsuke; Toshima Gen; Chijiiwa Yliki; Torikata Takao; Araki Tomohiro^*

来源：Bioscience Biotechnology and Biochemistry, 2012, 76(4): 691-698.

DOI：10.1271/bbb.110819

• lysozyme
• amino acid sequence
• lysozyme-catalyzed reaction
• site-directed mutagenesis
• subsite

The amino acid sequence of Egyptian goose lysozyme (EGL) from egg-white and its enzymatic properties were analyzed. The established sequence had the highest similarity to wood duck lysozyme (WDL) with five amino acid substitutions, and had eighteen substitutions difference from hen egg-white lysozyme (HEL). Tyr34 and Gly37 were found at subsites E and F of the active site when compared with FEEL. The experimental time-course characteristics of EGL against the N-acetylglucosamine pentamer substrate, (GlcNAc)(5), revealed higher production of (GlcNAc)(4) and lower production of (GlcNAc)(2) when compared with HEL. The saccharide-binding ability of subsites A-C in EGL was also found to be weaker than in HEL. An analysis of the enzymatic reactions of five mutants in respect of positions 34, 37 and 71 in HEL indicated the time-course characteristics of EGL to be caused by the combination of three substitutions (F34Y, N37G and G71R) between HEL and EGL. A computer simulation of the EGL-catalyzed reaction suggested that the time-course characteristics of EGL resulted from the difference in the binding free energy for subsites A, B, E and F and the rate constant of transglycosylation between EGL and HEL.

• 出版日期2012-4