Glycosylation at Asn‐289 facilitates the ligand‐induced conformational changes of human Glu‐plasminogen

FEBS Letters

Mølgaard, Lone¹  Ponting, Chris P³  Christensen, Ulla² 

[1] Biologics Development, Novo Nordisk A/S, Hagedornsvej 1, DK-2820 Gentofte, Denmark;Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark;University of Oxford, Fibrinolysis Research Unit, The Old Observatory, South Parks Road, Oxford OX1 3RH, United Kingdom

关键词: Glu-plasminogen;    conformation of;    Glu-plasminogen;    glycoforms;    Lysine binding site;    AH site;    Stopped-flow kinetics;    Fibrinolysis;    regulation of;    6-AHA;    6-aminohexanoic acid;    t-AMCHA;    trans-4-aminomethyl-cyclohexane carboxylic acid;    LBS;    lysine binding site;    K1–K5;    kringle-domains of Glu-plasminogen;    AH ligand;    amino hexyl ligand;    α2PI;    α2-proteinase inhibitor;    AH site;    amino hexyl site as defined in [17];   

DOI  :  10.1016/S0014-5793(97)00221-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Glu-plasminogen exists in two major glycoforms (I and II). Glycoform I contains carbohydrate chains linked to Asn-289 and Thr-346, whereas glycoform II is glycosylated only at Thr-346. Disparities in carbohydrate content lead to differences in the important functional properties of the zymogen, e.g. the kinetics of activation. The kinetics of the large ligand-induced conformational changes of each of the Glu-plasminogen glycoforms have been studied using stopped-flow fluorescence. The results are in accordance with a conformational change governed by positive co-operative binding at two weak lysine-binding sites. Additional glycosylation at Asn-289 in Glu-plasminogen I results in a two-fold increase in the overall dissociation constant of a ligand, trans-4-aminomethyl-cyclohexane carboxylic acid. This effect stems directly from the reaction step during which the conformational changes occur. This implies a higher population of Glu-plasminogen I in the open conformation even in the absence of ligands, and thus accounts for a higher rate of activation of Glu-plasminogen I, in comparison with Glu-plasminogen II.

【 授权许可】

Unknown