The human alpha(2)-plasmin inhibitor: functional characterization of the unique plasmin(ogen)-binding region

The human alpha(2)-plasmin inhibitor (A2PI) possesses unique N- and C-terminal extensions that significantly influence its biological activities. The C-terminal segment, A2PIC (Asn(398)-Lys(452)), contains six lysines thought to be involved in the binding to lysine-binding sites in the kringle domai...

Full description

Saved in:
Bibliographic Details
Published in:Cellular and molecular life sciences : CMLS 2010-05, Vol.67 (9), p.1505-1518
Main Authors: Gerber, Simon S, Lejon, Sofia, Locher, Michael, Schaller, Johann
Format: Article
Language:English
Subjects:
alpha-2-Antiplasmin - chemistry
alpha-2-Antiplasmin - genetics
alpha-2-Antiplasmin - metabolism
Amino Acid Sequence
Animals
Binding Sites
Fibrinolysin - chemistry
Fibrinolysin - genetics
Fibrinolysin - metabolism
Humans
Kringles
Lysine - chemistry
Lysine - metabolism
Models, Molecular
Molecular Sequence Data
Peptides - chemistry
Peptides - genetics
Peptides - metabolism
Plasminogen - chemistry
Plasminogen - genetics
Plasminogen - metabolism
Protein Binding
Protein Conformation
Recombinant Proteins - chemistry
Recombinant Proteins - genetics
Recombinant Proteins - metabolism
Sequence Alignment
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The human alpha(2)-plasmin inhibitor (A2PI) possesses unique N- and C-terminal extensions that significantly influence its biological activities. The C-terminal segment, A2PIC (Asn(398)-Lys(452)), contains six lysines thought to be involved in the binding to lysine-binding sites in the kringle domains of human plasminogen, of which four (Lys(422), Lys(429), Lys(436), Lys(452)) are completely and two (Lys(406), Lys(415)) are partially conserved. Multiple Lys to Ala mutants of A2PIC were expressed in Escherichia coli and used in intrinsic fluorescence titrations with kringle domains K1, K4, K4 + 5, and K1 + 2 + 3 of human plasminogen. We were able to identify the C-terminal Lys(452) as the main binding partner in recombinant A2PIC (rA2PIC) constructs with isolated kringles. We could show a cooperative, zipper-like enhancement of the interaction between C-terminal Lys(452) and internal Lys(436) of rA2PIC and isolated K1 + 2 + 3, whereas the other internal lysine residues contribute only to a minor extent to the binding process. Sulfated Tyr(445) in the unique C-terminal segment revealed no influence on the binding affinity to kringle domains.
ISSN:1420-9071
DOI:10.1007/s00018-010-0264-3