期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1974
卷号：71
期号：9
页码：3440-3444
DOI：10.1073/pnas.71.9.3440
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The structural analysis of the Fab' fragment of human myeloma immunoglobulin IgGl({lambda}) New has been extended to a nominal resolution of 2.0 A. Each of the structural subunits corresponding to the variable and to the constant homology regions of the light and heavy chains contains two irregular {beta}-sheets which are roughly parallel to each other and surround a tightly packed interior of hydrophobic side chains. About 50-60% of the amino-acid residues are included in {beta}-pleated sheets. Sequence alignments between the homology regions of Fab' New obtained by comparison of their three-dimensional structures are given. Some of the sequence variations observed in light and heavy chains and the role of the regions of hypervariable sequence in defining the size and shape of the active site of different immunoglobulin molecules are discussed on the basis of the three-dimensional model of Fab' New.
关键词：β-sheets ; sequence alignments ; hypervariable regions ; active site
