Conserved structural features in class I major fimbrial subunits (Pilin) in gram-negative bacteria. Molecular basis of classification in seven subfamilies and identification of intrasubfamily sequence signature motifs which might be implicated in quaternary structure
Conserved structural features in class I major fimbrial subunits (Pilin) in gram-negative bacteria. Molecular basis of classification in seven subfamilies and identification of intrasubfamily sequence signature motifs which might be implicated in quaternary structure
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DOI：
10.1007/s002390010045
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发表时间：
2000-05-01
影响因子：
3.9
通讯作者：
Callebaut, I
中科院分区：
文献类型：
--
作者：
Girardeau, JP;Bertin, Y;Callebaut, I
1型和P菌毛是革兰氏阴性菌产生的I类菌毛的原型成员。尽管有共同的结构特征，低水平的氨基酸序列保守的I类主要菌毛亚基（菌毛蛋白）表明相当大的进化距离这个超家族的成员之间。我们强调在这里，I类菌毛蛋白的二维序列分析，使用疏水聚类分析（HCA）和二级结构预测（PHD程序）之间的结构相关性。我们目前的证据表明，所有成员的I类菌毛蛋白家族有明确的结构相关性，并建议分类的基础上系统发育分析的I类菌毛蛋白到7个亚科相关的氨基酸序列的结构特性的差异。使用一个敏感的比对过程（HCA），我们确定了29个残基的拓扑疏水性的位置，可能发挥突出的作用，折叠。区分不同菌毛蛋白亚家族的最引人注目的方面是（i）连接结构保守区域的环长度的巨大变化和（ii）位于预测为p-构象的区域上的亚家族内序列特征基序。我们认为，这些“intrasubfamily序列签名图案”的一部分，参与亚基-亚基相互作用的相互作用的表面。这些图案证明非常有用的新I类菌毛的特征和分类尚未被描述，其序列明显偏离那些特征组。（在我们的手稿提交后，I类菌毛亚基的实验结构发表了。根据这些实际的菌毛蛋白结构，在预测结果和证明中添加的注释中的晶体结构之间进行了比较。
Type 1 and P-pili are prototype members of Class I fimbriae produced by Gram-negative bacteria. Despite common structural characteristics, the low level of amino acid sequence conservation among the Class I major fimbrial subunits (pilins) indicates considerable evolutionary distance between members of this superfamily. We highlight here structural relatedness between Class I pilins from their two-dimensional sequence analysis using hydrophobic cluster analysis (HCA) and secondary structure predictions (PHD program). We present evidence that all members of the Class I pilin family have clear structural relatedness and suggest that classification based on phylogenetic analysis of Class I pilins into seven subfamilies correlates with differences in structural properties of the amino acid sequences. Using a sensitive alignment process (HCA), we identified 29 residues in topohydrophobic positions which probably play a prominent role in folding. The most striking aspects that distinguish the different pilin subfamilies are (i) large variation in the length of the loops connecting the structurally conserved regions and (ii) intrasubfamily sequence signature motifs located on regions predicted to be in the p-conformation. We suggest that these "intrasubfamily sequence signature motifs" are part of interactive surfaces which participate in subunit-subunit interactions. These motifs prove highly useful in characterizing and classifying new Class I fimbriae that have not yet been described and whose sequence diverges appreciably from those of characterized groups. (After the submission of our manuscript, the experimental structure of Class I pilus subunits was published. In light of these actual pilin structures, a comparison has been made between the predicted results and the crystal structure in the Note Added in Proof.).