Balian G, Click E M, Bornstein P
J Biol Chem. 1980 Apr 25;255(8):3234-6.
Preferential labeling of COOH-terminal sequences in newly synthesized fibronectin was achieved by short term incorporation of radiolabeled amino acids in the presence of pactamycin, an inhibitor of polypeptide chain initiation. The labeled fibronectin was then cleaved with cathepsin D under conditions that yield a large (137,000-dalton) fragment that lacks collagen-binding properties, and a smaller (72,000-dalton) fragment that retains the ability of fibronectin to bind to collagen. Determination of the relative specific radioactivities of the two fragments leads us to conclude that the collagen-binding domain in fibronectin is located in the NH2-terminal third of the polypeptide chain and not in a COOH-terminal region as previously indicated by other structural studies.
在放线菌酮（一种多肽链起始抑制剂）存在的情况下，通过短期掺入放射性标记氨基酸，实现了对新合成纤连蛋白中羧基末端序列的优先标记。然后，在能产生一个缺乏胶原结合特性的大（137,000道尔顿）片段和一个保留纤连蛋白与胶原结合能力的较小（72,000道尔顿）片段的条件下，用组织蛋白酶D切割标记的纤连蛋白。对这两个片段相对比放射性的测定使我们得出结论，纤连蛋白中的胶原结合结构域位于多肽链氨基末端的三分之一处，而不是如先前其他结构研究所示位于羧基末端区域。
