Halkides C J, Redfield A G
Department of Biochemistry, Brandeis University, Waltham, MA 02254, USA.
J Biomol NMR. 1995 Jun;5(4):362-6. doi: 10.1007/BF00182279.
The relaxation rates of the multiple-quantum coherence for the amide hydrogen of Gly13 in ras p21.GDP were determined in the presence and absence of 17O labeling in the beta-phosphate of GDP. No significant difference could be observed between labeled and unlabeled samples, in spite of the fact that the hydrogen bond from the amide group of Gly13 to the beta-phosphate is shorter than is typical, based on its chemical shift. For macromolecules in which an oxygen atom is the acceptor of a hydrogen bond, dipolar coupling between 17O and hydrogen is unlikely to be observable, except for extremely short H-bonds.
在GDP的β-磷酸基团存在和不存在17O标记的情况下，测定了ras p21·GDP中Gly13酰胺氢的多量子相干弛豫速率。尽管基于化学位移，Gly13酰胺基团与β-磷酸基团之间的氢键比典型氢键短，但在标记和未标记的样品之间未观察到显著差异。对于氧原子作为氢键受体的大分子，除了极短的氢键外，17O与氢之间的偶极耦合不太可能被观察到。
