Structure-function studies of the SERPIN plasminogen activator inhibitor type 1. Analysis of chimeric strained loop mutants.
1990 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 265, no 33, 20293-301 p.Article in journal (Refereed) Published
Three chimeric mutants of plasminogen activator inhibitor 1 (PAI-1) have been constructed where the strained loop of wild type PAI-1 (wtPAI-1) has been replaced with a 19-amino acid region from either plasminogen activator inhibitor 2 (PAI-2), antithrombin III, or with an artificial serine protease inhibitor superfamily consensus strained loop. The inhibitors were expressed in Escherichia coli, and the purified proteins had specific activities toward urokinase-type plasminogen activator (uPA) or the single- and two-chain forms of tissue type plasminogen activator (tPA) that were similar to wtPAI-1. Experiments suggest that the strained loop of PAI-1 is not responsible for the transition between the latent and the active conformations or for binding to vitronectin. Second-order rate constants for the interactions with uPA and single- or two-chain tPA were similar to those of wtPAI-1. Values range from a low of 1.8 x 10(5) M-1 s-1 for the interaction of the PAI-2 chimera with single-chain tPA to a high value of 1.6 x 10(7) M-1 s-1 for the consensus mutant with two-chain tPA. This former value is 200 times higher than the reported rate constant for the interaction between PAI-2 and single-chain tPA, suggesting that structures outside of the strained loop are responsible for the major differences in specificity between PAI-1 and PAI-2.
Place, publisher, year, edition, pages
1990. Vol. 265, no 33, 20293-301 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:umu:diva-59895PubMedID: 1700786OAI: oai:DiVA.org:umu-59895DiVA: diva2:556996