Glutaminase of Micrococcus luteus K-3 (intact glutaminase; 48 kDa) is digested to a C-terminally truncated fragment (glutaminase fragment; 42 kDa) that shows higher salt tolerance than that of the intact glutaminase. The crystal structure of the glutaminase fragment was determined at 2.4 Å resolution using multiple-wavelength anomalous dispersion (MAD). The glutaminase fragment is composed of N-terminal and C-terminal domains, and a putative catalytic serine-lysine dyad (S64 and K67) is located in a cleft of the N-terminal domain. Mutations of the S64 or K67 residues abolished the enzyme activity. The N-terminal domain has abundant glutamic acid residues on its surface, which may explain its salt-tolerant mechanism. A diffraction analysis of the intact glutaminase crystals (a twinning fraction of 0.43) located the glutaminase fragment in the unit cell but failed to turn up clear densities for the missing C-terminal portion of the molecule. © 2006 Elsevier Inc. All rights reserved.
CITATION STYLE
Yoshimune, K., Shirakihara, Y., Shiratori, A., Wakayama, M., Chantawannakul, P., & Moriguchi, M. (2006). Crystal structure of a major fragment of the salt-tolerant glutaminase from Micrococcus luteus K-3. Biochemical and Biophysical Research Communications, 346(4), 1118–1124. https://doi.org/10.1016/j.bbrc.2006.04.188
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