CRYSTAL-STRUCTURE AND MOLECULAR-STRUCTURE OF A COLLAGEN-LIKE PEPTIDE AT 1.9-ANGSTROM RESOLUTION
CRYSTAL-STRUCTURE AND MOLECULAR-STRUCTURE OF A COLLAGEN-LIKE PEPTIDE AT 1.9-ANGSTROM RESOLUTION
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DOI：
10.1126/science.7695699
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发表时间：
1994-10-07
期刊：
影响因子：
56.9
通讯作者：
BERMAN, HM
中科院分区：
文献类型：
--
作者：
BELLA, J;EATON, M;BERMAN, HM
蛋白质三螺旋的结构已经通过对含有单一取代的共有序列的胶原蛋白样肽的X射线晶体学研究在1.9埃分辨率下确定。该肽采用三螺旋结构，证实了从胶原蛋白的纤维衍射研究确定的基本特征：聚脯氨酸II螺旋的超螺旋和链间氢键，遵循Rich和Crick模型II。此外，该结构提供了关于这种蛋白质折叠的性质的新信息。每一个三重螺旋都被一个水化圆柱体所包围，在水分子和肽受体基团之间有一个广泛的氢键网络。羟脯氨酸残基在这个水网络中起着关键作用。晶体中三股螺旋的轴间距与胶原纤维中的轴间距相似，并且晶体结构中连接相邻三股螺旋的水网络可能存在于结缔组织中。通过Gly->Ala取代打破重复（X-Y-Gly）模式会导致构象发生微妙变化，并导致三重螺旋局部解扭。在取代位点，直接的链间氢键被肽基团之间的间隙水桥取代。类似的构象变化可能发生在Gly->X突变的胶原蛋白中，这些胶原蛋白导致骨生成障碍、软骨发育不良和Ehlers-Danlos综合征IV。
The structure of a protein triple helix has been determined at 1.9 angstrom resolution by x-ray crystallographic studies of a collagen-like peptide containing a single substitution of the consensus sequence. This peptide adopts a triple-helical structure that confirms the basic features determined from fiber diffraction studies on collagen: supercoiling of polyproline II helices and interchain hydrogen bonding that follows the model II of Rich and Crick. In addition, the structure provides new information concerning the nature of this protein fold. Each triple helix is surrounded by a cylinder of hydration, with an extensive hydrogen bonding network between water molecules and peptide acceptor groups. Hydroxyproline residues have a critical role in this water network. The interaxial spacing of triple helices in the crystal is similar to that in collagen fibrils, and the water networks linking adjacent triple helices in the crystal structure are likely to be present in connective tissues. The breaking of the repeating (X-Y-Gly), pattern by a Gly-->Ala substitution results in a subtle alteration of the conformation, with a local untwisting of the triple helix. At the substitution site, direct interchain hydrogen bonds are replaced with interstitial water bridges between the peptide groups. Similar conformational changes may occur in Gly-->X mutated collagens responsible for the diseases osteogenesis imperfecta, chondrodysplasias, and Ehlers-Danlos syndrome IV.