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LIVER STEROL CARRIER PROTEINS--EFFECTS OF ETHANOL

肝脏甾醇载体蛋白——乙醇的影响

基本信息

批准号：
2748451
负责人：
WELLINGTON GIBSON WOOD
金额：
$ 16.54万
依托单位：
UNIVERSITY OF MINNESOTA
依托单位国家：
美国
项目类别：
财政年份：
1996
资助国家：
美国
起止时间：
1996-08-01 至 2001-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/2748451
关键词：
alcoholic beverage consumption binding proteins chemical binding cholesterol ethanol fatty acid binding protein fluorescent dye /probe intermolecular interaction laboratory mouse lipid transport liver metabolism membrane permeability nuclear magnetic resonance spectroscopy phospholipids protein structure function steroid metabolism transport proteins

项目摘要

DESCRIPTION (from Applicant's Abstract): Both lipids and proteins are sites of ethanol action. There have been an extensive number of studies on effects of ethanol on lipid structure. However, while quite a few studies examined effects of ethanol on protein function, there is little information known on how ethanol actually alters protein activity. It has been previously proposed that ethanol directly binds to proteins, but that conclusion has been largely based on effects of ethanol o protein function. Another issue is if ethanol directly binds to a protein what are the consequences of that binding on protein function. Preliminary data indicate that ethanol indeed directly binds to certain lipid transfer proteins, i.e., sterol carrier binding protein-2 (SCP-2), liver-fatty acid binding protein (L-FABP) and bovine serum albumin (BSA). In addition, we observed that ethanol displaced cis-parinaric acid from some, but not all fatty acid-binding sites on BSA. Thus, not only does ethanol directly bind to some proteins but it selectively binds to certain hydrophobic sites. It is the overall hypothesis of this new application that ethanol directly binds to hydrophobic areas of SCP-2 and L-FABP, two proteins that are affected by chronic ethanol consumption. We further proposed that ethanol inhibits the binding of endogenous ligands to SCP-2 and L-FABP and modifies sterol transport between membranes. These hypotheses will be examined using the powerful combination of fluorescence spectroscopy and 13C NMR relaxation technique. The specific aims of this application are: 1) characteristics of cholesterol phospholipids and fatty acids binding to SCP-2 and L-FABP will be examined in the absence and presence of ethanol in vitro using fluorescence techniques; 2) the binding geometry of ethanol and fatty acids to SCP-2 and L-FABP will be studied using 13C- ethanol NMR relaxation data; and 3) effects of SCP-2 and L-FABP enhanced sterol exchange between liver membranes will be evaluated. Chronic alcohol abuse is the most important cause of morbidity and mortality from liver disease in the United States. Approximately 90 percent of heavy alcohol drinkers develop fatty liver, resulting mainly from marked abnormalities in hepatic lipid metabolism, specifically, from accumulation of triacylglycerols and other lipids. In addition to lipids accumulating in liver with chronic ethanol consumption, proteins accumulate as well. Cytosolic proteins are largely responsible for this increase and L-FABP which binds fatty acids and cholesterol accounted for 22 percent of the total increase in liver cytosolic proteins in chronic ethanol treated rats. Therefore, it is important to understand how ethanol may directly act on L- FABP and SCP-2 with respect to binding, displacement of endogenous ligands, and lipid transport.

描述（来自申请人的摘要）：脂质和蛋白质都是乙醇作用的部位。有大量的研究表明乙醇对脂质结构的影响。然而，虽然不少研究检查了乙醇对蛋白质功能的影响，几乎没有关于乙醇如何改变蛋白质活性的已知信息。它先前已经提出乙醇直接与蛋白质结合，但这一结论在很大程度上是基于乙醇的影响。蛋白质功能另一个问题是，如果乙醇直接结合到蛋白质结合对蛋白质功能的影响。初步数据表明，乙醇确实直接结合到某些脂质转移蛋白，即，甾醇载体结合蛋白-2（SCP-2），肝脂肪酸结合蛋白（L-FABP）和牛血清白蛋白（BSA）。此外，我们观察到乙醇取代了顺式帕里纳克酸从一些，但不是所有的脂肪酸结合位点的BSA。因此不乙醇只会直接与某些蛋白质结合，与某些疏水位点结合。这是一个总体假设，这种新的应用，乙醇直接结合到疏水区域， SCP-2和L-FABP，两种受慢性乙醇影响的蛋白质消费我们进一步提出，乙醇抑制了 SCP-2和L-FABP的内源性配体，并改变固醇转运在膜之间。这些假设将使用强大的荧光光谱和13 C NMR弛豫的组合法本申请的具体目的是：1）胆固醇磷脂和脂肪酸结合的特性将在不存在和存在乙醇的情况下检查SCP-2和L-FABP 在体外使用荧光技术; 2）的结合几何乙醇和脂肪酸对SCP-2和L-FABP的影响将使用13 C- 乙醇NMR弛豫数据;和3）SCP-2和L-FABP增强的作用评价肝膜之间的固醇交换。慢性酗酒是发病和死亡的最重要原因肝脏疾病在美国。大约90%的大量饮酒者会患上脂肪肝，主要是由于肝脏脂质代谢异常，特别是三酰基甘油和其他脂质的积累。除了脂质在肝脏中蓄积，伴慢性乙醇消耗，蛋白质积累也是。胞浆蛋白质是主要负责这一点增加和L-FABP结合脂肪酸和胆固醇占对于22%的肝细胞溶质蛋白的总增加，慢性乙醇处理的大鼠。因此，重要的是要了解乙醇如何直接作用于L-FABP和SCP-2，结合、内源性配体的置换和脂质转运。