MCP-1: Structure/activity analysis
MCP-1: Structure/activity analysis
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DOI：
10.1006/meth.1996.0083
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发表时间：
1996-01-01
期刊：
影响因子：
--
通讯作者：
Rollins, Barrett J.
中科院分区：
文献类型：
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作者：
Zhang, Yujun;Ernst, Catherine A.;Rollins, Barrett J.
单核细胞趋化蛋白-1（MCP-1）功能的结构/活性关系已通过定点诱变进行了探索，并表明MCP-1的N-末端在激活MCP-1受体，特别是天冬氨酸-3中起着关键作用。然而，单核细胞趋化基序类似的ELR序列的嗜中性粒细胞活性趋化因子尚未被确定。其侧链从MCP-1的第一个β折叠片的一面突出的氨基酸也与精氨酸-24一样参与生物活性。在C-C趋化因子中，位置24仅在MCP-1、MCP-2和MCP-3中被精氨酸占据，表明精氨酸可能是单核细胞趋化因子特异性的取代。几种MCP-1变体拮抗野生型MCP-1活性，最有效的是N-末端缺失变体。一种缺少氨基酸2-8的变体（称为7 ND）响应于野生型MCP-1而抑制单核细胞趋化性，但不响应于化学交联的MCP-1同源二聚体。这表明N-末端缺失变体作为显性负抑制剂发挥其作用，这意味着MCP-1将其受体活化为二聚体。这具有深远的生物学意义，也表明二聚体界面可能是MCP-1抑制剂的靶点。最后，诱变已经证明鼠MCP-1由两个结构域组成。与人MCP-1共线的N-末端结构域包含鼠MCP-1的所有化学引诱物活性。富含丝氨酸和苏氨酸的49个氨基酸的C-末端结构域含有大量的O-连接的碳水化合物，其占鼠MCP-1表观分子大小的50%。
Structure/activity relationships underlying the function of monocyte chemoattractant protein-1 (MCP-1) have been probed by site-directed mutagenesis and indicate that the N-terminus of MCP-1 plays a critical role in activating the MCP-1 receptor, especially aspartate-3. However, a monocyte chemoattractant motif analogous to the ELR sequence of neutrophil-active chemokines has not yet been identified. Amino acids whose side chains project from one face of the first beta-pleated sheet of MCP-1 are also involved in biological activity as is arginine-24. Among C-C chemokines, position 24 is occupied by arginine only in MCP-1, -2, and -3, suggesting that arginine may be a substitution specific for monocyte chemoattractants. Several MCP-1 variants antagonize wild-type MCP-1 activity, the most potent being N-terminal deletion variants. One such variant lacking amino acids 2-8 (called 7ND) inhibits monocyte chemotaxis in response to wild-type MCP-1, but not in response to chemically crosslinked MCP-1 homodimers. This indicates that N-terminal deletion variants exert their effects as dominant negative inhibitors, which implies that MCP-1 activates its receptor as a dimer. This has profound biological implications and also suggests that the dimer interface may be a target for MCP-1 inhibitors. Finally, mutagenesis has demonstrated that murine MCP-1 consists of two domains. An N-terminal domain colinear with human MCP-1 contains all of murine MCP-1's chemoattractant activity. A C-terminal domain of 49 amino acids, which is rich in serine and threonine, contains an extensive amount of 0-linked carbohydrate that accounts for 50% of murine MCP-1's apparent molecular size.