PDBsum entry 1bda

Hydrolase/hydrolase inhibitor

PDB id: 1bda

Contents

Protein chain

265 a.a. *

Ligands

2Z0 ×2

Waters ×19

* Residue conservation analysis

PDB id:

1bda

Name:

Hydrolase/hydrolase inhibitor

Title:

Catalytic domain of human single chain tissue plasminogen activator in complex with dansyl-egr-cmk (dansyl-glu-gly-arg chloromethyl ketone)

Structure:

Single chain tissue type plasminogen activator. Chain: a, b. Fragment: unp residues 298-562. Synonym: sc-tpa. Engineered: yes. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 562

Biol. unit:

Dimer (from PQS)

Resolution:

3.35Å R-factor: not given

Authors:

W.Bode,M.Renatus,R.A.Engh

Key ref:

M.Renatus et al. (1997). Lysine 156 promotes the anomalous proenzyme activity of tPA: X-ray crystal structure of single-chain human tPA. EMBO J, 16, 4797-4805. PubMed id: 9305622 DOI: 10.1093/emboj/16.16.4797

Date:

07-May-98 Release date: 11-May-99

Protein chains

P00750  (TPA_HUMAN) -  Tissue-type plasminogen activator from Homo sapiens

Seq: 562 a.a.

Struc: 265 a.a.

Enzyme reactions

• Enzyme class: E.C.3.4.21.68 - t-plasminogen activator.
• Reaction: Specific cleavage of Arg-|-Val bond in plasminogen to form plasmin.

DOI no: 10.1093/emboj/16.16.4797

EMBO J 16:4797-4805 (1997)

PubMed id: 9305622

Lysine 156 promotes the anomalous proenzyme activity of tPA: X-ray crystal structure of single-chain human tPA.

M.Renatus, R.A.Engh, M.T.Stubbs, R.Huber, S.Fischer, U.Kohnert, W.Bode.

ABSTRACT

Tissue type plasminogen activator (tPA) is the physiological initiator of fibrinolysis, activating plasminogen via highly specific proteolysis; plasmin then degrades fibrin with relatively broad specificity. Unlike other chymotrypsin family serine proteinases, tPA is proteolytically active in a single-chain form. This form is also preferred for therapeutic administration of tPA in cases of acute myocardial infarction. The proteolytic cleavage which activates most other chymotrypsin family serine proteinases increases the catalytic efficiency of tPA only 5- to 10-fold. The X-ray crystal structure of the catalytic domain of recombinant human single-chain tPA shows that Lys156 forms a salt bridge with Asp194, promoting an active conformation in the single-chain form. Comparisons with the structures of other serine proteinases that also possess Lys156, such as trypsin, factor Xa and human urokinase plasminogen activator (uPA), identify a set of secondary interactions which are required for Lys156 to fulfil this activating role. These findings help explain the anomalous single-chain activity of tPA and may suggest strategies for design of new therapeutic plasminogen activators.

Selected figure(s)

Figure 1.
Figure 1 Stereo ribbon plot of the catalytic domain of sc-tPA in 'standard' orientation. The inhibitor (dansyl-Glu-Gly-Arg-chloromethylketone) shown by green sticks is covalently bonded to Ser195 and His57 of the catalytic triad. Key sc-tPA residues are shown as yellow sticks: Asp102, His57 and Ser195 of the catalytic triad; Asp189 at the base of the S1 specificity pocket; and Asp194 and Lys156 which form a salt bridge in the activation pocket. The red ribbon shows the conformation of the N-terminal activation loop which includes the plasmin cleavage site. Some loops arranged around the active site are labelled: the mainly disordered 37 loop and the 110 loop to the east; the partially disordered 186 loop to the south-west is in proximity to the activation loop. The figure was made with SETOR (Evans, 1993).

Figure 2.
Figure 2 Stereo plot of the activation domain environment of sc-tPA involving residues of the activation pocket, the activation loop and Lys156. Lys156 (blue) stabilizes the active conformation of sc-tPA via formation of a salt bridge with Asp194 (red). The strength of this interaction is presumably increased by the concerted solvent shielding effect of the (red) activation loop and of the hydrophobic residues Ile16, Phe21 and His144 (yellow). Lysines 17 and 143, which were considered potential activators of sc-tPA (Wallén et al., 1983; Petersen et al., 1990) are also shown (blue). Residues His188, Arg186A and Asn186F of the 186 loop (yellow) are presumed to be responsible for the conformational stabilization of this loop.

The above figures are reprinted from an Open Access publication published by Macmillan Publishers Ltd: EMBO J (1997, 16, 4797-4805) copyright 1997.

Figures were selected by an automated process.