title: Splice junctions: association with variation in protein structure.
abstract: A comparison between eukaryotic gene sequences and protein sequences of homologous enzymes from bacterial and mammalian organisms shows that intron-exon junctions frequently coincide with variable surface loops of the protein structures. The altered surface structures can account for functional differences among the members of a family. Sliding of the intron-exon junctions may constitute one mechanism for generating length polymorphisms and divergent sequences found in protein families. Since intron-exon junctions map to protein surfaces, the alterations mediated by sliding of these junctions can be effected without disrupting the stability of the protein core.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins; D001483:Base Sequence; D005075:Biological Evolution; D004247:DNA / Q000235:genetics; D010450:Endopeptidases / Q000235:genetics; D005057:Eukaryotic Cells / Q000378:metabolism; D005796:Genes; D005798:Genes, Bacterial; D011487:Protein Conformation; D011506:Proteins / Q000235:genetics*; D012697:Serine Endopeptidases; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011506:Proteins; D004247:DNA; D013762:Tetrahydrofolate Dehydrogenase; D010450:Endopeptidases; D012697:Serine Endopeptidases; C024983:streptogrisin A