2GMK

Crystal structure of onconase double mutant with spontaneously-assembled (AMP) 4 stack


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.165 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural basis for catalysis by onconase.

Lee, J.E.Bae, E.Bingman, C.A.Phillips Jr., G.N.Raines, R.T.

(2008) J.Mol.Biol. 375: 165-177

  • DOI: 10.1016/j.jmb.2007.09.089
  • Primary Citation of Related Structures:  2I5S

  • PubMed Abstract: 
  • Onconase (ONC) is a homolog of bovine pancreatic ribonuclease (RNase A) from the frog Rana pipiens. ONC displays antitumoral activity and is in advanced clinical trials for the treatment of cancer. Here, we report the first atomic structures of ONC-n ...

    Onconase (ONC) is a homolog of bovine pancreatic ribonuclease (RNase A) from the frog Rana pipiens. ONC displays antitumoral activity and is in advanced clinical trials for the treatment of cancer. Here, we report the first atomic structures of ONC-nucleic acid complexes: a T89N/E91A ONC-5'-AMP complex at 1.65 A resolution and a wild-type ONC-d(AUGA) complex at 1.90 A resolution. The latter structure and site-directed mutagenesis were used to reveal the atomic basis for substrate recognition and turnover by ONC. The residues in ONC that are proximal to the scissile phosphodiester bond (His10, Lys31, and His97) and uracil nucleobase (Thr35, Asp67, and Phe98) are conserved from RNase A and serve to generate a similar bell-shaped pH versus k(cat)/K(M) profile for RNA cleavage. Glu91 of ONC forms two hydrogen bonds with the guanine nucleobase in d(AUGA), and Thr89 is in close proximity to that nucleobase. Installing a neutral or cationic residue at position 91 or an asparagine residue at position 89 virtually eliminated the 10(2)-fold guanine:adenine preference of ONC. A variant that combined such substitutions, T89N/E91A ONC, actually preferred adenine over guanine. In contrast, installing an arginine residue at position 91 increased the guanine preference and afforded an ONC variant with the highest known k(cat)/K(M) value. These data indicate that ONC discriminates between guanine and adenine by using Coulombic interactions and a network of hydrogen bonds. The structure of the ONC-d(AUGA) complex was also used to probe other aspects of catalysis. For example, the T5R substitution, designed to create a favorable Coulombic interaction between ONC and a phosphoryl group in RNA, increased ribonucleolytic activity by twofold. No variant, however, was more toxic to human cancer cells than wild-type ONC. Together, these findings provide a cynosure for understanding catalysis of RNA cleavage in a system of high medicinal relevance.


    Organizational Affiliation

    Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
P-30 protein
A
104Lithobates pipiensEC: 3.1.27.-
Find proteins for P22069 (Lithobates pipiens)
Go to UniProtKB:  P22069
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
AMP
Query on AMP

Download SDF File 
Download CCD File 
A
ADENOSINE MONOPHOSPHATE
C10 H14 N5 O7 P
UDMBCSSLTHHNCD-KQYNXXCUSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
PCA
Query on PCA
A
L-PEPTIDE LINKINGC5 H7 N O3GLU
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
AMPKi: 590000 nM BINDINGMOAD
AMPKi: 590000 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.165 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 28.994α = 90.00
b = 52.112β = 90.00
c = 66.142γ = 90.00
Software Package:
Software NamePurpose
SAINTdata scaling
PDB_EXTRACTdata extraction
REFMACrefinement
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-04-25
    Type: Initial release
  • Version 1.1: 2008-01-15
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance