Thermodynamic And Kinetic Studies Of Protein Structure A

本实验室主要研究蛋白质序列、结构与蛋白质折叠机制及酶促反应之间的关系。(i)不溶性蛋白质的二级结构蛋白质在溶液中的结构很容易通过圆二色性（CD）光谱的数学分析来估计。与朊病毒疾病有关的蛋白质是不溶性的，必须作为薄膜进行研究。在这些情况下，蛋白质浓度，这通常是必要的定量和分析的CD数据不能确定。我们已经展示了一种与浓度无关的结构测定方法，该方法涉及蛋白质的“g因子”光谱的测量和去卷积，g因子光谱是样品CD和吸收光谱的比率。(ii)胱硫醚β合酶的结构（与Edith Wilson Miles博士和同事，LBG）我们正在研究色氨酸合酶α 2-β 2复合物的构象状态及其在蛋白质酶促机制中的相关性。(iii)哺乳动物硫转移酶的结构。(with Dr. D.马歇尔和W.B.博士Jakoby，LBM）来自大鼠肝脏的苯酚磺基转移酶的酶活性已被证明通过生理浓度的谷胱甘肽对保守的特定半胱氨酸残基的可逆氧化/还原来调节。半胱氨酸残基66的氧化通过非常紧密的底物抑制来抑制酶的生理活性。这种机制可能是重要的氧化应激条件下的肝脏。(iv)轮状病毒蛋白NSP 2的结构（与Peter Schuck博士，ORS，OD和Z. Taraporewala，LID，NIAID）这种蛋白质是病毒复制装置的组成部分，与RNA和核苷酸相互作用。我们正在研究它的结构和与配体相互作用引起的变化。

This laboratory is interested in the relationship among protein sequence, structure and the mechanisms of protein folding and enzymic reactions. (i) Secondary Structure of Insoluble Proteins. The structure of a protein in solution is readily estimated by mathematical analysis of its circular dichroism (CD)spectrum. Proteins implicated in prion diseases are insoluble and must be studied as thin films. Under these circumstances, protein concentration, which is usually necessary for quantification and analysis of CD data cannot be determined. We have shown a concentration independent method of structure determination, which involves measurement and deconvolution of the protein's "g-factor" spectrum, which is the ratio of a samples CD and absorbance spectra. (ii) Structure of Cystathionine beta Synthase (with Dr. Edith Wilson Miles and coworkers, LBG) We are investigating the conformational states of the tryptophan synthase alpha2-beta2 complex and their relevance in the enzymatic mechanism of the protein. (iii) Structure of Mammalian Sulphotransferases. (with Dr. D. Marshall and Dr. W.B. Jakoby, LBM) The enzymatic activity of a phenol sulphotransferase, from rat liver, has been shown to be regulated by reversible oxidation/reduction of a conserved specific cysteine residue by physiological concentrations of glutathione. Oxdation of cysteine residue 66 inhibits the physiological activity of the enzyme by very tight substrate inhibition. This mechanism may be important under conditions of oxidative stress to the liver. (iv) Structure of Rotavirus protein NSP2 (with Dr. Peter Schuck, ORS, OD and Dr. Z. Taraporewala, LID, NIAID) This protein is a component of the virus' replication apparatus, interacting with RNA and nucleotides. We are studying its structure and the changes induced by interaction with ligands.