کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1940965 | 1050792 | 2006 | 7 صفحه PDF | دانلود رایگان |

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.
Journal: Biochemical and Biophysical Research Communications - Volume 346, Issue 4, 11 August 2006, Pages 1118–1124