Schumacher M A, Zheleznova E E, Poundstone K S, Kluger R, Jones R T, Brennan R G
Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97201-3098, USA.
Proc Natl Acad Sci U S A. 1997 Jul 22;94(15):7841-4. doi: 10.1073/pnas.94.15.7841.
Hemoglobin has been a long-standing paradigm for understanding protein allostery. Here, the x-ray structures of two chemically crosslinked, fully liganded hemoglobins, alpha2beta82CA82beta and alpha2beta82ND82beta, are described at 2.3 A and 2.6 A resolution, respectively. Strikingly, these crosslinked hemoglobins assume intermediate conformations that lie between those of R and the controversial liganded hemoglobin state R2 rather than between R and T. Thus, these structures support only a T left and right arrow R left and right arrow R2 allosteric pathway and underscore the physiological importance of the R2 conformation.
血红蛋白一直是理解蛋白质别构作用的长期范例。在此，分别以2.3埃和2.6埃分辨率描述了两种化学交联的、完全配体化的血红蛋白α2β82CA82β和α2β82ND82β的x射线结构。引人注目的是，这些交联血红蛋白呈现出介于R态和有争议的配体化血红蛋白状态R2之间的中间构象，而非介于R态和T态之间。因此，这些结构仅支持T⇌R⇌R2别构途径，并突出了R2构象的生理重要性。
