Proteins in load-bearing junctions: the histidine-rich metal-binding protein of mussel byssus.
Proteins in load-bearing junctions: the histidine-rich metal-binding protein of mussel byssus.
复制标题
承载连接中的蛋白质：贻贝足丝富含组氨酸的金属结合蛋白。
DOI：
10.1021/bi061677n
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发表时间：
2006
期刊：
影响因子：
2.9
通讯作者：
Waite,JHerbert
中科院分区：
文献类型：
--
作者：
Zhao,Hua;Waite,JHerbert
构建复杂的承重支架依赖于功能不同的生物大分子的有效连接方式。贻贝足中胶原纤维和泡沫样粘附斑块之间的连接是坚固的，尽管其连接结构明显不同。从加利福尼亚贻贝足部组织中分离并鉴定了mcfp-4基质蛋白及其预分泌形式。通过MALDI-TOF质谱测定，mcfp-4的质量为~ 93 kDa。其组成以组氨酸为主（22摩尔%），但赖氨酸、精氨酸和天冬氨酸的含量也很显著。氨基酸分析和氧化还原循环试验可检测到少量3,4-二羟基苯基-l-丙氨酸（2 mol %）。dna推断的mcfp-4序列揭示了具有高度重复内部结构的多个变体，包括n端一半的约36个连续重复的富含his的十肽（例如，HVHTHRVLHK）和c端一半的16个更退化的富含天冬氨酸的非肽（例如，DDHVNDIAQTA）。用富含his的十肽与Fe3+、Co2+、Ni2+、Zn2+和Cu2+孵育合成的肽表明，只有Cu是强结合的。用焦碳酸二乙酯修饰的肽在Cu结合前后的MALDI-TOF质谱分析表明，组氨酸残基主导了Cu结合。相反，富含天冬氨酸的非肽优先结合Ca2+。mcfp-4利用金属离子将其自身的富含his的结构域偶联到前cols的富含his的末端，从而战略性地定位为大分子双功能连接体。Ca2+可能介导c端与其他钙结合斑块蛋白的偶联。
Building complex load-bearing scaffolds depends on effective ways of joining functionally different biomacromolecules. The junction between collagen fibers and foamlike adhesive plaques in mussel byssus is robust despite the strikingly dissimilar connected structures. mcfp-4, the matrix protein from this junction, and its presecreted form from the foot tissue ofMytilus californianuswere isolated and characterized. mcfp-4 has a mass of ∼93 kDa as determined by MALDI-TOF mass spectrometry. Its composition is dominated by histidine (22 mol %), but levels of lysine, arginine, and aspartate are also significant. A small amount of 3,4-dihydroxyphenyl-l-alanine (2 mol %) can be detected by amino acid analysis and redox cycling assays. The cDNA-deduced sequence of mcfp-4 reveals multiple variants with highly repetitive internal structures, including ∼36 tandemly repeated His-rich decapeptides (e.g., HVHTHRVLHK) in the N-terminal half and 16 somewhat more degenerate aspartate-rich undecapeptides (e.g., DDHVNDIAQTA) in the C-terminal half. Incubation of a synthetic peptide based on the His-rich decapeptide with Fe3+, Co2+, Ni2+, Zn2+, and Cu2+indicates that only Cu is strongly bound. MALDI-TOF mass spectrometry of the peptide modified with diethyl pyrocarbonate before and after Cu binding suggests that histidine residues dominate Cu binding. In contrast, the aspartate-rich undecapeptides preferentially bind Ca2+. mcfp-4 is strategically positioned to function as a macromolecular bifunctional linker by using metal ions to couple its own His-rich domains to the His-rich termini of the preCOLs. Ca2+may mediate coupling of the C-terminus to other calcium-binding plaque proteins.