کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1939887 | 1050769 | 2006 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Structural basis for the alteration of coenzyme specificity in a malate dehydrogenase mutant Structural basis for the alteration of coenzyme specificity in a malate dehydrogenase mutant](/preview/png/1939887.png)
To elucidate the structural basis for the alteration of coenzyme specificity from NADH toward NADPH in a malate dehydrogenase mutant EX7 from Thermus flavus, we determined the crystal structures at 2.0 Å resolution of EX7 complexed with NADPH and NADH, respectively. In the EX7-NADPH complex, Ser42 and Ser45 form hydrogen bonds with the 2′-phosphate group of the adenine ribose of NADPH, although the adenine moiety is not seen in the electron density map. In contrast, although Ser42 and Ser45 occupy a similar position in the EX7-NADH complex structure, both the adenine and adenine ribose moieties of NADH are missing in the map. These results and kinetic analysis of site-directed mutant enzymes indicate (1) that the preference of EX7 for NADPH over NADH is ascribed to the recognition of the 2′-phosphate group by two Ser and Arg44, and (2) that the adenine moiety of NADPH is not recognized in this mutant.
Journal: Biochemical and Biophysical Research Communications - Volume 347, Issue 2, 25 August 2006, Pages 502–508