2ODY

Thrombin-bound boophilin displays a functional and accessible reactive-site loop


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.190 
  • R-Value Observed: 0.192 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Isolation, cloning and structural characterisation of boophilin, a multifunctional kunitz-type proteinase inhibitor from the cattle tick.

Macedo-Ribeiro, S.Almeida, C.Calisto, B.M.Friedrich, T.Mentele, R.Sturzebecher, J.Fuentes-Prior, P.Pereira, P.J.

(2008) PLoS One 3: e1624-e1624

  • DOI: 10.1371/journal.pone.0001624
  • Primary Citation of Related Structures:  
    2ODY

  • PubMed Abstract: 
  • Inhibitors of coagulation factors from blood-feeding animals display a wide variety of structural motifs and inhibition mechanisms. We have isolated a novel inhibitor from the cattle tick Boophilus microplus, one of the most widespread parasites of farm animals ...

    Inhibitors of coagulation factors from blood-feeding animals display a wide variety of structural motifs and inhibition mechanisms. We have isolated a novel inhibitor from the cattle tick Boophilus microplus, one of the most widespread parasites of farm animals. The inhibitor, which we have termed boophilin, has been cloned and overexpressed in Escherichia coli. Mature boophilin is composed of two canonical Kunitz-type domains, and inhibits not only the major procoagulant enzyme, thrombin, but in addition, and by contrast to all other previously characterised natural thrombin inhibitors, significantly interferes with the proteolytic activity of other serine proteinases such as trypsin and plasmin. The crystal structure of the bovine alpha-thrombin.boophilin complex, refined at 2.35 A resolution reveals a non-canonical binding mode to the proteinase. The N-terminal region of the mature inhibitor, Q16-R17-N18, binds in a parallel manner across the active site of the proteinase, with the guanidinium group of R17 anchored in the S(1) pocket, while the C-terminal Kunitz domain is negatively charged and docks into the basic exosite I of thrombin. This binding mode resembles the previously characterised thrombin inhibitor, ornithodorin which, unlike boophilin, is composed of two distorted Kunitz modules. Unexpectedly, both boophilin domains adopt markedly different orientations when compared to those of ornithodorin, in its complex with thrombin. The N-terminal boophilin domain rotates 9 degrees and is displaced by 6 A, while the C-terminal domain rotates almost 6 degrees accompanied by a 3 A displacement. The reactive-site loop of the N-terminal Kunitz domain of boophilin with its P(1) residue, K31, is fully solvent exposed and could thus bind a second trypsin-like proteinase without sterical restraints. This finding explains the formation of a ternary thrombin.boophilin.trypsin complex, and suggests a mechanism for prothrombinase inhibition in vivo.


    Organizational Affiliation

    Centro de Neurociências e Biologia Celular (CNC), Coimbra, Portugal.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Prothrombin (EC 3.4.21.5)A, C49Bos taurusMutation(s): 0 
Gene Names: F2
EC: 3.4.21.5
Find proteins for P00735 (Bos taurus)
Explore P00735 
Go to UniProtKB:  P00735
Protein Feature View
Expand
  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Prothrombin (EC 3.4.21.5)B, D259Bos taurusMutation(s): 0 
Gene Names: F2
EC: 3.4.21.5
Find proteins for P00735 (Bos taurus)
Explore P00735 
Go to UniProtKB:  P00735
Protein Feature View
Expand
  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
BoophilinE, F127Rhipicephalus microplusMutation(s): 0 
Gene Names: H2
Find proteins for Q8WPI2 (Rhipicephalus microplus)
Explore Q8WPI2 
Go to UniProtKB:  Q8WPI2
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download Ideal Coordinates CCD File 
K [auth D]2-acetamido-2-deoxy-beta-D-glucopyranose
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
PO4
Query on PO4

Download Ideal Coordinates CCD File 
G [auth A], H [auth B], I [auth B], M [auth F]PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
NA
Query on NA

Download Ideal Coordinates CCD File 
J [auth B], L [auth D]SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.190 
  • R-Value Observed: 0.192 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 92.5α = 90
b = 104.2β = 90
c = 129.1γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling
AMoREphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-01-22
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Derived calculations, Version format compliance
  • Version 1.2: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Data collection, Derived calculations, Structure summary