MUTATIONAL ANALYSIS AND MOLECULAR MODELING OF THE N-TERMINAL KRINGLE-CONTAINING DOMAIN OF HEPATOCYTE GROWTH-FACTOR IDENTIFIES AMINO-ACID SIDE-CHAINS IMPORTANT FOR INTERACTION WITH THE C-MET RECEPTOR
MUTATIONAL ANALYSIS AND MOLECULAR MODELING OF THE N-TERMINAL KRINGLE-CONTAINING DOMAIN OF HEPATOCYTE GROWTH-FACTOR IDENTIFIES AMINO-ACID SIDE-CHAINS IMPORTANT FOR INTERACTION WITH THE C-MET RECEPTOR
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DOI：
10.1093/protein/7.7.895
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发表时间：
1994-07-01
期刊：
影响因子：
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通讯作者：
GODOWSKI, PJ
中科院分区：
文献类型：
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作者：
LOKKER, NA;PRESTA, LG;GODOWSKI, PJ
肝细胞生长因子受体（hepatocyte growth factor receptor，HGFr）介导多种生物信号，包括有丝分裂、运动和形态发生。我们最近定位了肝细胞生长因子（HGF）的N-末端175个氨基酸内的区域，称为HGF/NK 1，这是必要的和足够的结合到HGFr。HGF/NK1包含一个尚未结构化的N-末端区域，随后是四个HGF kringles中的第一个。我们已经使用了分子建模和诱变的组合来剖析HGF的这一区域的功能。在HGF kringle 1（K1）的拟议表面区域上鉴定出两个突变敏感的斑块。第一个补丁由残基E159、S161、E195和R197组成，所有这些残基预计在K1的三级结构中彼此接近。第二块位于Kringle的相对侧，由残基D171和Q173组成。对HGF N末端区域的突变分析鉴定出残基D117，该残基似乎也影响受体结合。我们还研究了一种天然存在的HGF变体（Delta 5-HGF）的特性，该变体来自选择性剪接的转录本，因此在K1内缺少5个残基。我们的数据表明，在野生型HGF中，F162在维持Kringle的疏水核心中至关重要。在Delta 5-HGF中，该残基的丢失通过用Y167功能性取代F162来补偿，预计Y167占据Delta 5-HGF K1核心。野生型和Delta 5 kringles模型的比较表明，假定的受体结合决定簇的位置保持不变。这些研究为野生型和Delta 5-HGF的受体结合特性提供了结构基础，并为Kringle介导的蛋白质-蛋白质相互作用的机制提供了重要线索。
The hepatocyte growth factor receptor (HGFr) transduces a wide range of biological signals, including mitogenesis, motogenesis and morphogenesis. We recently localized a region within the N-terminal 175 amino acids of hepatocyte growth factor (HGF), termed HGF/NK1, that is necessary and sufficient for binding to the HGFr. HGF/NK1 contains an as-yet structurally undefined N-terminal region followed by the first of four HGF kringles. We have used a combination of molecular modeling and mutagenesis to dissect the function of this region of HGF. Two mutation-sensitive patches on the proposed surface regions of HGF kringle one (K1) were identified. The first patch consists of residues E159, S161, E195 and R197, all of which are predicted to be close to each other in the tertiary structure of K1. The second patch, lying on the opposite side of the kringle, consists of residues D171 and Q173. Mutational analysis of the N-terminal region of HGF identified residue D117 which also appeared to influence receptor binding. We also investigated the properties of a naturally occurring HGF variant (Delta 5-HGF) that arises from an alternatively spliced transcript and therefore lacks five residues within K1. Our data suggest that in wild-type HGF, F162 is crucial in maintaining the hydrophobic core of the kringle. In Delta 5-HGF, the loss of this residue is compensated for by a functional substitution of F162 with Y167, which is predicted to occupy the Delta 5-HGF K1 core. Comparison of the models of wild-type and Delta 5 kringles reveals that the positions of the presumed receptor binding determinants remain unchanged. These studies suggest a structural basis for the receptor binding properties of wild-type and Delta 5-HGF and provide important clues as to the mechanism of kringle-mediated protein - protein interactions.