Cardin A D, Behnke W D
Biochim Biophys Acta. 1978 Dec 20;537(2):436-45. doi: 10.1016/0005-2795(78)90528-7.
Studies on the circular dichroic spectrum of cobalt-substituted concanavalin A have been continued in particular with respect to calcium- and saccharide-induced spectral pertubations reported previously (Kalb, A.J. and Pecht, I. (1973) Biochim. Biophys. Acta 303, 264-268; Richardson, C.E. and Behnke, W.D. (1976) J. Mol. Biol. 102, 441-451). We find that the addition of calcium or cadmium to (CO2+)-concanavalin A induces slow time-dependent alterations in the extrinsic cotton effects. Moreover, one equivalent of calcium is sufficient to cause maximal changes in the cobalt spectrum provided sufficient time is allowed for the effect to be observed. The addition of mono, di-and trisaccharides, specific for concanavalin A, have no resolvable effect upon the cobalt spectrum of concanavalin A (Richardson, C.E. and Behnke, W.D. (1976) J. Mol. Biol. 102, 441-451). The data presented here suggest that these time-dependent processes are conformationally mediated and occur subsequent to S2 occupancy. Evidence is presented that a particular calcium-cobalt-concanavalin A conformer exists which is responsible for the generation of activity in a light-scattering assay system.
关于钴取代伴刀豆球蛋白A的圆二色光谱的研究仍在继续，尤其针对先前报道的钙和糖类诱导的光谱扰动（卡尔布，A.J.和佩希特，I.（1973年）《生物化学与生物物理学学报》303卷，264 - 268页；理查森，C.E.和贝恩克，W.D.（1976年）《分子生物学杂志》102卷，441 - 451页）。我们发现，向（CO2 +） - 伴刀豆球蛋白A中添加钙或镉会诱导外在棉效应随时间缓慢变化。此外，如果有足够时间观察到这种效应，一当量的钙足以使钴光谱发生最大变化。添加对伴刀豆球蛋白A具有特异性的单糖、二糖和三糖，对伴刀豆球蛋白A的钴光谱没有可分辨的影响（理查森，C.E.和贝恩克，W.D.（1976年）《分子生物学杂志》102卷，441 - 451页）。此处给出的数据表明，这些随时间变化的过程是由构象介导的，且发生在S2占据之后。有证据表明存在一种特定的钙 - 钴 - 伴刀豆球蛋白A构象体，它在光散射测定系统中负责产生活性。
