2-DIMENSIONAL NMR ASSIGNMENTS AND CONFORMATION OF (PRO-HYP-GLY)(10) AND A DESIGNED COLLAGEN TRIPLE-HELICAL PEPTIDE
2-DIMENSIONAL NMR ASSIGNMENTS AND CONFORMATION OF (PRO-HYP-GLY)(10) AND A DESIGNED COLLAGEN TRIPLE-HELICAL PEPTIDE
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DOI：
10.1021/bi00080a007
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发表时间：
1993-07-27
期刊：
影响因子：
2.9
通讯作者：
BAUM, J
中科院分区：
文献类型：
--
作者：
LI, MH;FAN, P;BAUM, J
本文用同向和异向二维核磁共振方法研究了两个三螺旋多肽。一种肽（POG）10被认为是三螺旋的最稳定原型。第二个肽，（POG）3 ITGARGLAGPOG（POG）3（表示为T3-785），设计用于模拟胶原蛋白的亚氨基酸贫乏区域，并含有来自III型胶原蛋白中独特胶原酶切割位点附近的12个残基。两种肽均以三聚体形式缔合，（POG）10的解链温度为60 ℃，T3-785肽的解链温度为25 ℃。序列特异性分配的三肽单位POG（POG）10，和80%的POG三联体被发现是在一个等效的环境。在T3-785中，由于序列中引入了非重复的X-Y-Gly单元，因此可以通过NMR区分同三聚体的三条链。的溶液构象（POG）10是非常相似的模型，从X-射线纤维衍射数据，虽然肽含有较低的有序区域的肽末端。在T3-785的三聚体形式中，三条链的中心残基紧密堆积，并且数据与具有三条平行链的一个残基交错的三螺旋模型一致。对于T3-785，与（POG）10相反，也存在来自较不有序形式的共振，这可能是由于存在少量单体。T3-785和（POG）10骨架构象的相似性表明，在亚氨基酸贫乏区域不存在替代构象。
Homonuclear and heteronuclear 2D NMR methods are used to study two triple-helical peptides. One peptide, (POG)10, is considered to be the most stable prototype of a triple helix. The second peptide, (POG)3ITGARGLAGPOG(POG)3 (denoted T3-785), was designed to model an imino acid poor region of collagen and contains 12 residues from near the unique collagenase cleavage site in type III collagen. Both peptides associated as trimers, with melting temperatures of 60-degrees-C for (POG)10 and 25-degrees-C for the T3-785 peptide. Sequence-specific assignments were made for a tripeptide unit POG in (POG)10, and 80% of the POG triplets are found to be in an equivalent environment. In T3-785, with nonrepeating X-Y-Gly units incorporated in the sequence, the three chains of the homotrimer can be distinguished from one another by NMR. The solution conformation of (POG)10 is very similar to the model derived from X-ray fiber diffraction data, although the peptide contains less ordered regions at the peptide ends. In the trimer form of T3-785, the central residues of the three chains are closely packed, and the data are consistent with a triple-helical model with a one-residue stagger of three parallel chains. For T3-785, in contrast to (POG)10, there are also resonances from a less ordered form, which are probably due to the presence of a small amount of monomer. The similarity of the backbone conformations of T3-785 and (POG)10 suggests that an alternative conformation is not present in the imino acid poor region.