title: Synthesis, conformation and reactivity towards p-nitrophenyl acetate of polypeptides incorporating aspartic acid, serine and histidine.
abstract: Examination of beta-carbons coordinates of seryl, aspartyl and histidyl residues in active sites of alpha-chymotrypsin and subtilisin BPN' shows that a close geometrical arrangement can be obtained in an antiparellel beta-structure. Therefore some polypeptides incorporating serine, aspartic acid and histidine, poly (Gly-Ser-Asp-His-Ala-Pro) and poly [(Asp-Leu-AsP-Leu)10,  (His-Leu-Ser-Leu)1], and expected to have some tendency to give rise to an antiparallel beta-conformation, have been prepared and studied. The second polymer only adopts a fairly well-defined beta-structure in aqueous solution. Catalytic activities of these products towards p-nitrophenyl acetate are not improved as compared to histidine. However, kinetic pK of histidine side-chain depends markedly upon the nature of the product, owing probably to a hydrophobic environment effect.
mesh_terms: D000595:Amino Acid Sequence; D001224:Aspartic Acid; D001665:Binding Sites; D002918:Chymotrypsin / Q000378:metabolism; D002942:Circular Dichroism; D006639:Histidine; D009596:Nitrophenols; D010455:Peptides / Q000138:chemical synthesis; D011487:Protein Conformation; D012694:Serine; D013055:Spectrophotometry, Infrared; D013329:Structure-Activity Relationship; D013381:Subtilisins / Q000378:metabolism
chemical_list: D009596:Nitrophenols; D010455:Peptides; D001224:Aspartic Acid; D012694:Serine; D006639:Histidine; C008642:4-nitrophenyl acetate; D013381:Subtilisins; D002918:Chymotrypsin