Proteins that bind calcium in a phospholipid-dependent manner.
Proteins that bind calcium in a phospholipid-dependent manner.
复制标题
以磷脂依赖性方式结合钙的蛋白质。
DOI：
10.1021/bi00218a013
复制
发表时间：
1991
期刊：
影响因子：
2.9
通讯作者：
Nelsestuen,GL
中科院分区：
文献类型：
--
作者：
Bazzi,MD;Nelsestuen,GL
明尼苏达大学生物化学系，圣保罗，明尼苏达州55108摘要：从牛脑中纯化了以钙依赖性方式与磷脂结合的三种蛋白（Mr-64K， 32K和22K）。通过平衡透析和凝胶过滤色谱法研究了这些蛋白的钙结合特性。64- kda和32-kDa蛋白具有与蛋白激酶C惊人相似的钙和磷脂结合特性[Bazzi， M. D., & nelson， G. L.(1990) Biochemistry 29, 7624]，游离蛋白结合限制二价金属离子，即使在200 juM钙。然而，在含有酸性磷脂的膜存在的情况下，它们将每个蛋白质结合8到9个钙离子。两种蛋白结合所需的钙浓度不同，且受囊泡磷脂组成的强烈影响；高磷脂酰丝氨酸含量的囊泡需要较低浓度的钙才能使蛋白质-膜结合。这些性质描述了一种一般类型的钙相互作用系统，其中需要所有三种成分（蛋白质、磷脂和钙）同时相互作用。游离蛋白可能仅为每个钙离子提供部分配位键，但在蛋白质-磷脂界面上可以产生完整的钙结合位点。与64- kda和32-kDa蛋白相比，22-kDa蛋白在存在或不存在磷脂的情况下结合了相似数量的钙（2到3个离子/蛋白）。22 kda蛋白对磷脂的亲和力最低，对钙的亲和力最高。因此，钙依赖性磷脂结合蛋白由几种类型组成。以磷脂依赖方式的钙结合可能构成细胞中钙反应元件的主要类型。例如，64-和32-kDa蛋白似乎相当丰富，甚至可能作为钙缓冲剂调节信号事件。
Department of Biochemistry, University of Minnesota, St. Paul, Minnesota 55108 Received August 7, 1990; Revised Manuscript Received October 17, 1990 abstract: Three proteins (Mr-64K, 32K, and 22K) that bindto phospholipids in a calcium-dependent manner were purified from bovine brain. The calcium-binding properties of these proteins were investigated by equilibrium dialysis and by gel filtration chromatography. The 64-and 32-kDa proteins were found to have calcium-and phospholipid-binding properties strikingly similar to those of protein kinase C [Bazzi, M. D., & Nelsestuen, G. L.(1990) Biochemistry 29, 7624], The free proteins bound limited divalent metal ion even at 200 juM calcium. However, they bound eight to nine calcium ions per protein in the presence of membranes containing acidic phospholipids. The calcium concentrations needed for protein-phospholipid binding were different for these two proteins and were strongly influenced by the phospholipid composition of the vesicles; vesicles of higher phosphatidylserine content required lower concentrations of calcium for protein-membrane association. These properties described a general type of calcium-interacting system where simultaneous interaction of all three components (protein, phospholipids, and calcium) is required. The free proteins may provide only partial coordinate bonds to each calcium ion, but complete calcium-binding sites could be generated at the protein-phospholipid interface. In contrastto the 64-and 32-kDa proteins, the 22-kDa protein bound similar amounts of calcium (two to three ions/protein) inthe presence or the absence of phospholipids. The 22-kDa protein had the lowest affinity for phospholipid and the highest affinity for calcium of the three proteins tested. Thus, calcium-dependent phospholipid-binding proteins consist of several types. Calcium binding in a phospholipid-dependent manner may constitute a major type of calcium-response element in the cell. For example, the 64-and 32-kDa proteins appear to be quite abundant and may even function as a calcium buffer to modulate signaling events.