Causgrove T, Goss D J, Parkhurst L J
Biochemistry. 1984 May 8;23(10):2168-73. doi: 10.1021/bi00305a010.
Hybrid hemoglobins have been made in which one chain is derived from human hemoglobin and the other from carp hemoglobin. Both hybrid hemoglobins show low cooperativity in oxygen binding. Hybrid I (alpha carp: beta human) has a very small Bohr effect, whereas hybrid II (alpha human: beta carp) has a Bohr effect nearly as large as that for human hemoglobin. Both hemoglobins have P50's more closely resembling carp hemoglobin than human hemoglobin in the region of pH 7, and for both hybrids, as for carp, cooperativity virtually disappears at acid and alkaline pHs. Since both hybrids are formed from chains derived from cooperative parent hemoglobins, it is difficult to account for the low cooperativity in terms only of the T-state salt bridges and the alpha 1-beta 2 contacts involved in the R-T switch region. We suggest that the F9 Ser in the carp beta-chain as well as alpha 1-beta 1 interactions is important in controlling the allosteric transitions in these hybrids.
已经制备出了杂合血红蛋白，其中一条链来源于人血红蛋白，另一条来源于鲤鱼血红蛋白。两种杂合血红蛋白在氧结合方面都表现出低协同性。杂合体I（α链来自鲤鱼：β链来自人）的玻尔效应非常小，而杂合体II（α链来自人：β链来自鲤鱼）的玻尔效应几乎与人血红蛋白的一样大。在pH 7的范围内，两种血红蛋白的P50更接近鲤鱼血红蛋白而不是人血红蛋白，并且对于这两种杂合体，如同鲤鱼血红蛋白一样，在酸性和碱性pH条件下协同性几乎消失。由于这两种杂合体都是由具有协同性的亲本血红蛋白的链形成的，因此仅根据R-T转换区域中涉及的T态盐桥和α1-β2接触来解释低协同性是困难的。我们认为，鲤鱼β链中的F9丝氨酸以及α1-β1相互作用对于控制这些杂合体中的变构转变很重要。
