1PJ8

Structure of a ternary complex of proteinase K, mercury and a substrate-analogue hexapeptide at 2.2 A resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Work: 0.170 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of a ternary complex of proteinase K, mercury, and a substrate-analogue hexa-peptide at 2.2 A resolution

Saxena, A.K.Singh, T.P.Peters, K.Fittkau, S.Visanji, M.Wilson, K.S.Betzel, C.

(1996) Proteins 25: 195-201

  • DOI: 10.1002/(SICI)1097-0134(199606)25:2<195::AID-PROT5>3.0.CO;2-H

  • PubMed Abstract: 
  • The crystal structure of a ternary complex of proteinase K, Hg(II) and a hexapeptide N-Ac-Pro-Ala-Pro-Phe-Pro-Ala-NH2 has been determined at 2.2 A resolution and refined to an R factor of 0.172 for 12,910 reflections. The mercury atom occupies two al ...

    The crystal structure of a ternary complex of proteinase K, Hg(II) and a hexapeptide N-Ac-Pro-Ala-Pro-Phe-Pro-Ala-NH2 has been determined at 2.2 A resolution and refined to an R factor of 0.172 for 12,910 reflections. The mercury atom occupies two alternate sites, each of which was assigned an occupancy of 0.45. These two sites are bridged by Cys-73 S gamma which forms covalent bonds to both. Both mercury sites form regular polyhedrons involving atoms from residues Asp-39, His-69, Cys-73, His-72, Met-225, and Wat-324. The complex formation with mercury seems to disturb the stereochemistry of the residues of the catalytic triad Asp-39, His-69, and Ser-224 appreciably, thus reducing the enzymatic activity of proteinase K to 15%. The electron density in the difference Fourier map shows that the hexapeptide occupies the S1 subsite predominantly and the standard recognition site constituted by Ser-132 to Gly-136 and Gly-100 to Tyr-104 segments is virtually empty. The hexapeptide is held firmly through a series of hydrogen bonds involving protein atoms and water molecules. As a result of complex formation, Asp-39, His-69, Met-225, Ile-220, Ser-219, Thr-223, and Ser-224 residues move appreciably to accommodate the mercury atoms and the hexapeptide. The largest movement is observed for Met-225 which is involved in multiple interactions with both mercury and the hexapeptide. The activity results indicate an inhibition rate of 95%, as a result of the combined effect of mercury and hexapeptide.


    Organizational Affiliation

    Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Proteinase K
A
279Engyodontium albumGene Names: PROK
EC: 3.4.21.64
Find proteins for P06873 (Engyodontium album)
Go to UniProtKB:  P06873
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
6-residue peptide (N-Ac-PAPFPA-NH2)
I
7N/AN/A
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HG
Query on HG

Download SDF File 
Download CCD File 
A
MERCURY (II) ION
Hg
BQPIGGFYSBELGY-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
NH2
Query on NH2
I
NON-POLYMERH2 N

--

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Work: 0.170 
  • Space Group: P 43 21 2
Unit Cell:
Length (Å)Angle (°)
a = 68.280α = 90.00
b = 68.280β = 90.00
c = 107.870γ = 90.00
Software Package:
Software NamePurpose
TRUNCATEdata reduction
CCP4data scaling
AMoREphasing
PROLSQrefinement
MOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-06-17
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Atomic model, Database references, Derived calculations, Non-polymer description, Structure summary, Version format compliance