A novel SNARE N-terminal domain revealed by the crystal structure of Sec22b
A novel SNARE N-terminal domain revealed by the crystal structure of Sec22b
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DOI：
10.1074/jbc.m101584200
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发表时间：
2001-06-29
影响因子：
4.8
通讯作者：
Scheller, RH
中科院分区：
文献类型：
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作者：
Gonzalez, LC;Weis, WI;Scheller, RH
细胞内膜融合通过来自相对膜的SNARE结合成稳定的α-螺旋束来促进。许多SNARE，除了它们的α-螺旋区域之外，还含有可能具有基本调节功能的N-末端结构域。为了更好地理解这种调节，我们已经确定了小鼠Sec 22 b（mSec 22 b）的130个氨基酸的N-末端结构域的2.4埃晶体结构，这是一种参与内质网/高尔基体膜运输的SNARE。该结构域由混合的α-螺旋/β-折叠组成，类似于肌动蛋白/聚脯氨酸结合蛋白、profilin和GAF/PAS家族调节模块的环状排列.该结构不同于先前表征的syntaxin 1A的N-末端结构域，并且与syntaxin 1A不同，mSec 22 b的N-末端结构域对SNARE体外组装的速率没有影响。表面保守残基的分析揭示了一个潜在的蛋白质相互作用位点。该位点中的关键残基在两种缺乏SNARE结构域的哺乳动物Sec 22变体中是不同的。最后，序列分析表明类似的结构域可能存在于内体/溶酶体SNARE VAMP 7中。
Intra-cellular membrane fusion is facilitated by the association of SNAREs from opposite membranes into stable alpha -helical bundles. Many SNAREs, in addition to their alpha -helical regions, contain N-terminal domains that likely have essential regulatory functions. To better understand this regulation, we have determined the 2.4-Angstrom crystal structure of the 130-amino acid N-terminal domain of mouse Sec22b (mSec22b), a SNARE involved in endoplasmic reticulum/Golgi membrane trafficking. The domain consists of a mixed alpha -helical/beta -sheet fold that resembles a circular permutation of the actin/polyproline binding protein, profilin, and the GAF/PAS family of regulatory modules. The structure is distinct from the previously characterized N-terminal domain of syn taxin 1A, and, unlike syntaxin 1A, the N-terminal domain of mSec22b has no effect on the rate of SNARE assembly in vitro. An analysis of surface conserved residues reveals a potential protein interaction site. Key residues in this site are distinct in two mammalian Sec22 variants that lack SNARE domains, Finally, sequence analysis indicates that a similar domain is likely present in the endosomal/lysosomal SNARE VAMP7.