title: Penta-L-lysine Potentiates Fibrin-Independent Activity of Human Tissue Plasminogen Activator.
creator: Rehan, Mohammad
creator: Sagar, Amin
creator: Sharma, Vandna
creator: Mishra, Sanskruti
creator: Ganguly, Ashish
creator: Sahni, Girish
subject: QR Microbiology
description: The therapeutic action of tissue plasminogen activator (t-PA) is a two-step process: (1) binding to lysine-rich fibrin (Km event) and (2) converting local plasminogen into plasmin (Kcat event). Overcoming limitations of other structural biophysics methods, we wanted to employ small-angle X-ray scattering (SAXS) to visualize what shape changes occur/accompany t-PA activation, but the prime hurdle was the polydisperse nature of the fibrin, which occluded scattering information from t-PA. Earlier, larger polylysine peptides have been used to potentiate activation of t-PA, so while screening short polylysine peptides as alternatives to fibrin or larger peptides, we found that penta-polylysine (P5) specifically activates t-PA in a dose-dependent manner, averaging to almost 3-fold more than in the absence of any peptide. SAXS data analysis confirmed that P5 does not induce association of t-PA molecules, and a narrower peak profile of the Kratky plot indicated that P5 binding quenches inherent motion in t-PA. Shape reconstruction of t-PA ∓ P5 revealed that P5 closes the "gap" between the two gross domains of t-PA, viz. fused F/E, K1 and K2 domains, and the P domain. Docking experiments suggested that, while other polylysine peptides preferentially interacted with the surfaces of kringle domains, P5 "slipped into" the gap/groove between K2 and P domains, thereby mediating a substantial increase in the number of long-range interactions between the K2 domain and exosites in the P domain. We report here dissection of shape events involved in between Km/Kcat steps of t-PA activation, which can pave the way toward the search for small molecule function regulator(s) of t-PA.
publisher: ACS Publications
date: 2015-10-22
type: Article
type: PeerReviewed
relation: http://pubs.acs.org/doi/10.1021/acs.jpcb.5b07735
identifier:   Rehan, Mohammad and Sagar, Amin and Sharma, Vandna and Mishra, Sanskruti and Ganguly, Ashish and Sahni, Girish  (2015) Penta-L-lysine Potentiates Fibrin-Independent Activity of Human Tissue Plasminogen Activator.  The journal of physical chemistry. B, 119 (42).  pp. 13271-7.  ISSN 1520-5207     
relation: http://crdd.osdd.net/open/1749/