RAMAN-SPECTROSCOPIC CHARACTERIZATION OF TRYPTOPHAN SIDE-CHAINS IN LYSOZYME BOUND TO INHIBITORS - ROLE OF THE HYDROPHOBIC BOX IN THE ENZYMATIC FUNCTION
RAMAN-SPECTROSCOPIC CHARACTERIZATION OF TRYPTOPHAN SIDE-CHAINS IN LYSOZYME BOUND TO INHIBITORS - ROLE OF THE HYDROPHOBIC BOX IN THE ENZYMATIC FUNCTION
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DOI：
10.1021/bi00238a035
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发表时间：
1991-06-18
期刊：
影响因子：
2.9
通讯作者：
HARADA, I
中科院分区：
文献类型：
--
作者：
MIURA, T;TAKEUCHI, H;HARADA, I
The state of H-bonding and the hydrophobic interaction of six tryptophan side chains in lysozyme bound to substrate-analogous inhibitors were investigated by combining H --> D exchange labeling and Raman difference spectroscopy. The frequency of the W17 band due to Trp-63 shifts downward upon inhibitor binding, indicating a specific and strong H-bond formation between the N1 site of the side chain and the inhibitor molecule. On the other hand, the H-bonding state of Trp-62 in the complex is as weak as that in inhibitor-free lysozyme, suggesting no contribution of this residue to the inhibitor binding. Intensity increases of W 1 7 and W 1 8 bands observed upon inhibitor binding are, respectively, ascribed to an increase at Trp-28 and a decrease at Trp-111 in hydrophobic interactions with the environment. The environmental changes are explained consistently by a movement of the Met-105 side chain sandwiched by two indole rings of Trp-28 and 111 in the direction from Trp-111 to Trp-28. The sandwich structure in a core domain, hydrophobic box, and its rearrangement are considered to play an important role in the enzymatic function of lysozyme.
