Engineering Enhanced Function into G. dibranchiata Monomer Hemoglobins

本提案的长期目标是了解如何 血红素蛋白结构调节血红素蛋白反应性。 该项目的重点是二鳃甘油单体 血红蛋白 有三种不同的单体血红蛋白， 其结构类似于脊椎动物肌红蛋白。 尽管如此，它们的动力学性质与 肌红蛋白，可能的原因是，在每个单体中， 血红蛋白末端组氨酸被亮氨酸取代。 在 例如，在氰化物结合的情况下， 与脊椎动物肌红蛋白相比明显无反应性。 一 这些珠蛋白cDNA序列已被克隆，测序， 在E. coli表达系统。 定点 还构建了突变体，以观察是否增强了 反应性可以被建立在天然非反应性结构中。 将研究野生型蛋白和定点突变体 使用动力学、平衡和NMR来实现以下目标： 将结构与功能联系起来。

The long-term objective of this proposal is to understand how heme protein architecture regulates heme protein reactivity. The project has as its focus the Glycera dibranchiata monomer hemoglobins. There are three distinct monomer hemoglobins two of which exhibit structures similar to vertebrate myoglobins. Despite this their kinetic properties differ significantly from myoglobin, for the probable reason that in each of the monomer hemoglobins the distal histidine is replaced by leucine. In the case of cyanide binding, for example, these proteins are notably unreactive in comparison to vertebrate myoglobins. One of these globin cDNA sequences has been cloned, sequenced and expressed in an E. coli expression system. Site-directed mutants have also been constructed to see if enhanced reactivity can be built in to a naturally unreactive structure. Wild-type proteins and site directed mutants will be studied using kinetics, equilibrium and NMR to fulfill the goal of relating structure to function.