CRYSTALLINE FIBRIL STRUCTURE OF TYPE-II COLLAGEN IN LAMPREY NOTOCHORD SHEATH
CRYSTALLINE FIBRIL STRUCTURE OF TYPE-II COLLAGEN IN LAMPREY NOTOCHORD SHEATH
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DOI：
10.1016/0022-2836(84)90424-8
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发表时间：
1984-01-01
影响因子：
5.6
通讯作者：
BRODSKY, B
中科院分区：
文献类型：
--
作者：
EIKENBERRY, EF;CHILDS, B;BRODSKY, B
报道了七鳃鳗脊索鞘原纤维中存在II型胶原的结晶分子堆积。这是第一次在I型胶原蛋白以外的任何胶原蛋白中发现晶体结构。七鳃鳗脊索鞘具有类似于软骨的组成，具有II型胶原，一种具有1 α的次要胶原成分，2.alpha. 3. alpha。链和软骨样蛋白聚糖。脊索中纤维的高度取向使得可以使用X射线衍射来确定这种含II型组织中的胶原纤维组织。低角赤道散射显示原纤维都是apprx。直径为17 nm，中心与中心的平均间距为31 nm。这些结果得到了EM观测的支持。在较高角度处的一组宽赤道衍射最大值表示通过有限的晶格对胶原分子转化的采样，其在接近1个原纤维直径的横向尺寸上延伸。每个17 nm的原纤维包含一个晶体阵列的分子，虽然一个单位细胞是难以确定的，因为广泛的重叠反射，准六边形的三斜晶系单位细胞的I型胶原蛋白在大鼠尾腱是不一致的数据。双相衍射图显示26级，肌腱的特征周期为67 nm。这些反射的强度显着不同，从肌腱发现，并不能解释一个未修改的间隙/重叠模型内的每个67 nm的周期。X-射线衍射和EM数据都表明沿原纤维轴沿着的对比度低，并且与非胶原成分的周期性结合一致，其结合方式使得差距区域模糊。
The existence of a crystalline molecular packing of type II collagen in the fibrils of the lamprey notochord sheath is reported. This is the 1st finding of a crystalline structure in any collagen other than type I. The lamprey notochord sheath has a composition similar to that of cartilage, with type II collagen, a minor collagen component with 1.alpha., 2.alpha. and 3.alpha. chains and cartilage-like proteoglycan. The high degree of orientation of fibrils in the notochord makes it possible to use X-ray diffraction to determine collagen fibril organization in this type II-containing tissue. The low angle equatorial scattering shows the fibrils are all .apprx. 17 nm in diameter and have an average center-to-center separation of 31 nm. These results are supported by EM observations. A set of broad equatorial diffraction maxima at higher angles represents the sampling of the collagen molecular transform by a limited crystalline lattice, extending over a lateral dimension close to the diameter of 1 fibril. Each 17 nm fibril contains a crystalline array of molecules and, although a unit cell is difficult to determine because of the broad overlapping reflections, the quasi-hexagonal triclinic unit cell of type I collagen in rat tail tendon is not consistent with the data. The meridional diffraction pattern showed 26 orders with the characteristic 67 nm periodicity found for tendon. The intensities of these reflections differ markedly from those found for tendon and cannot be explained by an unmodified gap/overlap model within each 67 nm period. Both X-ray diffraction and EM data indicate a low degree of contrast along the fibril axis and are consistent with a periodic binding of a non-collagenous component in such a way as to obscure the gap region.