Abstract
Using random mutagenesis, we previously obtained K33N mutant lysozyme that showed a large lytic halo on the plate coating Micrococcus luteus. In order to examine the effects of mutation of K33N on enzyme activity, we prepared K33N and K33A mutant lysozymes from yeast. It was found that the activities of both the mutant lysozymes were higher than those of the wild-type lysozyme based on the results of the activity measurements against M. luteus (lytic activity) and glycol chitin. Moreover, 3D structures of K33N and K33A mutant lysozyme were solved by X-ray crystallographic analyses. The side chain of K33 in the wild-type lysozyme hydrogen bonded with N37 involved in the substrate-binding region, and the orientation of the side chain of N37 in K33 mutant lysozymes were different in the wild-type lysozyme. These results suggest that the enhancement of activity in K33N mutant lysozyme was due to an alteration in the orientation of the side chain of N37. On the other hand, K33N lysozyme was less stable than the wild-type lysozyme. Lysozyme may sacrifice its enzyme activity to acquire the conformational stability at position 33.
| Original language | English |
|---|---|
| Pages (from-to) | 619-623 |
| Number of pages | 5 |
| Journal | Journal of biochemistry |
| Volume | 144 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - Nov 1 2008 |
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All Science Journal Classification (ASJC) codes
- Biochemistry
- Molecular Biology
Cite this
Crystal structures of K33 mutant hen lysozymes with enhanced activities. / Goto, Takashi; Ohkuri, Takatoshi; Shioi, Seijiro; Abe, Yoshito; Imoto, Taiji; Ueda, Tadashi.
In: Journal of biochemistry, Vol. 144, No. 5, 01.11.2008, p. 619-623.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Crystal structures of K33 mutant hen lysozymes with enhanced activities
AU - Goto, Takashi
AU - Ohkuri, Takatoshi
AU - Shioi, Seijiro
AU - Abe, Yoshito
AU - Imoto, Taiji
AU - Ueda, Tadashi
PY - 2008/11/1
Y1 - 2008/11/1
N2 - Using random mutagenesis, we previously obtained K33N mutant lysozyme that showed a large lytic halo on the plate coating Micrococcus luteus. In order to examine the effects of mutation of K33N on enzyme activity, we prepared K33N and K33A mutant lysozymes from yeast. It was found that the activities of both the mutant lysozymes were higher than those of the wild-type lysozyme based on the results of the activity measurements against M. luteus (lytic activity) and glycol chitin. Moreover, 3D structures of K33N and K33A mutant lysozyme were solved by X-ray crystallographic analyses. The side chain of K33 in the wild-type lysozyme hydrogen bonded with N37 involved in the substrate-binding region, and the orientation of the side chain of N37 in K33 mutant lysozymes were different in the wild-type lysozyme. These results suggest that the enhancement of activity in K33N mutant lysozyme was due to an alteration in the orientation of the side chain of N37. On the other hand, K33N lysozyme was less stable than the wild-type lysozyme. Lysozyme may sacrifice its enzyme activity to acquire the conformational stability at position 33.
AB - Using random mutagenesis, we previously obtained K33N mutant lysozyme that showed a large lytic halo on the plate coating Micrococcus luteus. In order to examine the effects of mutation of K33N on enzyme activity, we prepared K33N and K33A mutant lysozymes from yeast. It was found that the activities of both the mutant lysozymes were higher than those of the wild-type lysozyme based on the results of the activity measurements against M. luteus (lytic activity) and glycol chitin. Moreover, 3D structures of K33N and K33A mutant lysozyme were solved by X-ray crystallographic analyses. The side chain of K33 in the wild-type lysozyme hydrogen bonded with N37 involved in the substrate-binding region, and the orientation of the side chain of N37 in K33 mutant lysozymes were different in the wild-type lysozyme. These results suggest that the enhancement of activity in K33N mutant lysozyme was due to an alteration in the orientation of the side chain of N37. On the other hand, K33N lysozyme was less stable than the wild-type lysozyme. Lysozyme may sacrifice its enzyme activity to acquire the conformational stability at position 33.
UR - http://www.scopus.com/inward/record.url?scp=55349140077&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=55349140077&partnerID=8YFLogxK
U2 - 10.1093/jb/mvn108
DO - 10.1093/jb/mvn108
M3 - Article
C2 - 18776207
AN - SCOPUS:55349140077
VL - 144
SP - 619
EP - 623
JO - Journal of Biochemistry
JF - Journal of Biochemistry
SN - 0021-924X
IS - 5
ER -