Boudko Sergei P, Sasaki Takako, Engel Jürgen, Lerch Thomas F, Nix Jay, Chapman Michael S, Bächinger Hans Peter
Research Department of Shriners Hospital for Children, Portland, OR 97239, USA.
J Mol Biol. 2009 Sep 25;392(3):787-802. doi: 10.1016/j.jmb.2009.07.057. Epub 2009 Jul 23.
Collagens contain a unique triple-helical structure with a repeating sequence -G-X-Y-, where proline and hydroxyproline are major constituents in X and Y positions, respectively. Folding of the collagen triple helix requires trimerization domains. Once trimerized, collagen chains are correctly aligned and the folding of the triple helix proceeds in a zipper-like fashion. Here we report the isolation, characterization, and crystal structure of the trimerization domain of human type XVIII collagen, a member of the multiplexin family. This domain differs from all other known trimerization domains in other collagens and exhibits a high trimerization potential at picomolar concentrations. Strong chain association and high specificity of binding are needed for multiplexins, which are present at very low levels.
胶原蛋白含有独特的三螺旋结构，其具有重复序列-G-X-Y-，其中脯氨酸和羟脯氨酸分别是X和Y位置的主要成分。胶原蛋白三螺旋的折叠需要三聚化结构域。一旦三聚化，胶原蛋白链就会正确排列，三螺旋的折叠以拉链样方式进行。在此，我们报道了人XVIII型胶原蛋白三聚化结构域的分离、表征及晶体结构，XVIII型胶原蛋白是多重蛋白聚糖家族的成员。该结构域不同于其他胶原蛋白中所有已知的三聚化结构域，并且在皮摩尔浓度下表现出高三聚化潜力。多重蛋白聚糖存在水平极低，需要强链缔合和高结合特异性。
