 |
PDBsum entry 1db2
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Hydrolase inhibitor
|
PDB id
|
|
|
|
1db2
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
* Residue conservation analysis
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Plasminogen activator inhibitor 1. Structure of the native serpin, Comparison to its other conformers and implications for serpin inactivation.
|
|
|
Authors
|
|
H.Nar,
M.Bauer,
J.M.Stassen,
D.Lang,
A.Gils,
P.J.Declerck.
|
|
|
Ref.
|
|
J Mol Biol, 2000,
297,
683-695.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
The crystal structure of a constitutively active multiple site mutant of
plasminogen activator inhibitor 1 (PAI-1) was determined and refined at a
resolution of 2.7 A.The present structure comprises a dimer of two
crystallographically independent PAI-1 molecules that pack by association of the
residues P6 to P3 of the reactive centre loop of one molecule (A) with the edge
of the main beta-sheet A of the other molecule (B).Thus, the reactive centre
loop is ordered for molecule A by crystal packing forces, while for molecule B
it is unconstrained by crystal packing contacts and is disordered.The overall
structure of active PAI-1 is similar to the structures of other active
inhibitory serpins exhibiting as the major secondary structural feature a
five-stranded beta-sheet A and an intact proteinase-binding loop protruding from
the one end of the elongated molecule. No preinsertion of the reactive centre
loop is observed in this structure.A comparison of the present structure with
the previously determined crystal structures of PAI-1 in its alternative
conformations reveals that, upon cleavage of an intact form of PAI-1 or
formation of latent PAI-1, the well-characterised rearrangements of the serpin
secondary structural elements are accompanied by dramatic and partly unexpected
conformational changes of helical and loop structures proximal to beta-sheet
A.The present structure explains the stabilising effects of the mutated
residues, reveals the structural cause for the observed spectroscopic
differences between active and latent PAI-1, and provides new insights into
possible mechanisms of stabilisation by its natural binding partner, vitronectin.
|
|
|
|
|
|
|
|
Figure 7.
Figure 7. Stereo representation of the hD-s2A loop region
in active PAI-1 (blue) superimposed on the loop structure of the
peptide-bound form of PAI-1 (magenta). The loop adopts a totally
new conformation. The C-terminal end of hD is located further to
the left, compromising the new position of s2A in the closed
sheet A. W86 apparently is expelled from a partially buried
position behind hD in active PAI-1 to a fully external position
in latent, cleaved or peptide bound PAI-1. s2A is shorter by two
residues in active PAI-1 due to the loop rearrangement. The
hydrogen bond between N89 and H229 in the other PAI-1 conformers
is replaced by a hydrogen bond between E90 and H229.
|
|
Figure 9.
Figure 9. Surface representation of Figure 8 showing the
cavity formed in intact PAI-1 at the edge of sheet A between
helices D, E and strands s1A and s2A.
|
|
|
|
|
|
The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2000,
297,
683-695)
copyright 2000.
|
|
|
|
|
|
|
