title: Structural requirements of position A alpha-157 in fibrinogen for the fibrin-induced rate enhancement of the activation of plasminogen by tissue-type plasminogen activator.
abstract: The sequence fibrinogen-A alpha-(148-160) can mimic part of the fibrin-induced rate enhancement of the activation of plasminogen by tissue-type plasminogen activator. Previously we have reported that the lysine residue at position A alpha-157 is crucial. During our further investigations on A alpha-157 we found that lysine at position A alpha-157 may be replaced by glutamic acid. This unexpected finding prompted us to re-investigate the requirements of this position. We prepared analogues of A alpha-(148-160) in which the lysine residue at position A alpha-157 was replaced by lysine derivatives (acetyl-lysine, benzyloxycarbonyl-lysine and methanesulphonylethyloxycarbonyl-lysine), acidic residues (aspartic acid and glutamic acid), basic residues (arginine and ornithine), polar residues (glutamine and methanesulphonylethyloxycarbonylornithine), apolar residues (alanine, valine, norleucine and glutamic acid 4-nitrobenzyl ester) and glycine. These analogues were tested for their stimulatory activity. When aspartic acid, glutamic acid 4-nitrobenzyl ester or norleucine is present at position A alpha-157 in A alpha-(148-160) virtually all stimulatory capacity is lost. With valine at position A alpha-157 the stimulatory activity is marginal. None of the other replacements at position A alpha-157 caused loss of rate-enhancing properties. From these results we conclude that for the rate-enhancing effect of A alpha-(148-160) the side chain of the amino acid residue at position A alpha-157 must fulfill certain requirements: there must be one (as in alanine) or no (as in glycine) carbon atom in the side chain, or at least two carbon atoms and a polar group (charged or uncharged) to which a rather bulky group (such as the benzyloxycarbonyl group) or a polar group (such as the methanesulphonylethyloxycarbonyl group) may be attached. The highest activity [even higher than native A alpha-(148-160)] was obtained with ornithine, methanesulphonylethyloxycarbonylornithine or methanesulphonylethyloxycarbonyl-lysine at position A alpha-157.
authors.affiliation: Gaubius Laboratory IVVO-TNO, Leiden, The Netherlands.
authors.forename: J G
authors.initials: JG
authors.lastname: Schielen
authors.forename: H P
authors.initials: HP
authors.lastname: Adams
authors.forename: M
authors.initials: M
authors.lastname: Voskuilen
authors.forename: G J
authors.initials: GJ
authors.lastname: Tesser
authors.forename: W
authors.initials: W
authors.lastname: Nieuwenhuizen
mesh_terms: D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D004789:Enzyme Activation / Q000187:drug effects; D005337:Fibrin / Q000494:pharmacology*; D005340:Fibrinogen / Q000737:chemistry*; D008969:Molecular Sequence Data; D009904:Optical Rotation; D010958:Plasminogen / Q000378:metabolism*; D013329:Structure-Activity Relationship; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*
chemical_list: D005337:Fibrin; D005340:Fibrinogen; D010958:Plasminogen; D010959:Tissue Plasminogen Activator