کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10770154 | 1050829 | 2005 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Involvement in K+ access of Leu318 at the extracellular domain flanking M3 and M4 of the Na+,K+-ATPase α-subunit
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The effect of point mutation in the sequence 316TWLE319, which occurs in the extracellular loop flanking the third (M3) and the fourth (M4) transmembrane segment (L3/4) of the Na+,K+-ATPase α-subunit, was examined. Mutation of Glu319 to Asp yielded an enzyme with full activity, whereas substituting Glu319 to Ala resulted in a severe loss of activity. A negative charge was introduced along the sequence, one residue at a time, from Thr316 to Leu318 (by E-scanning) in the mutant construct with Glu319 already mutated to Gln. The activity that had been reduced to 60% by the mutation of Glu319 to Gln was restored upon the introduction of a negative charge by E-scanning. When Leu318 was replaced by Glu in a series of scanning experiments, the K+ sensitivity of the ATPase activity was lowered. The lowering of K+ sensitivity was further demonstrated when a mutation of Leu318 to Glu was introduced into the wild-type enzyme. Furthermore, mutants with Leu318 to Gln, Arg, and Phe displayed lower K+ sensitivity similar to that of Leu318 to Glu mutant. Leu318 may be in access path for K+, and any substitution at this position may interfere with access of K+ from outside the cell.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochemical and Biophysical Research Communications - Volume 330, Issue 2, 6 May 2005, Pages 611-614
Journal: Biochemical and Biophysical Research Communications - Volume 330, Issue 2, 6 May 2005, Pages 611-614
نویسندگان
Hiroshi Eguchi, Kazuo Takeda, Wolfgang Schwarz, Akira Shirahata, Masaru Kawamura,