5MNX

Neutron structure of cationic trypsin in complex with 2-aminopyridine


Experimental Data Snapshot

  • Method: NEUTRON DIFFRACTION
  • Resolution: 1.42 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.166 

wwPDB Validation 3D Report Full Report


This is version 2.1 of the entry. See complete history

Literature

Charges Shift Protonation: Neutron Diffraction Reveals that Aniline and 2-Aminopyridine Become Protonated Upon Binding to Trypsin.

Schiebel, J.Gaspari, R.Sandner, A.Ngo, K.Gerber, H.D.Cavalli, A.Ostermann, A.Heine, A.Klebe, G.

(2017) Angew. Chem. Int. Ed. Engl. 56: 4887-4890

  • DOI: 10.1002/anie.201701038
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Hydrogen atoms play a key role in protein-ligand recognition. They determine the quality of established H-bonding networks and define the protonation of bound ligands. Structural visualization of H atoms by X-ray crystallography is rarely possible. W ...

    Hydrogen atoms play a key role in protein-ligand recognition. They determine the quality of established H-bonding networks and define the protonation of bound ligands. Structural visualization of H atoms by X-ray crystallography is rarely possible. We used neutron diffraction to determine the positions of the hydrogen atoms in the ligands aniline and 2-aminopyridine bound to the archetypical serine protease trypsin. The resulting structures show the best resolution so far achieved for proteins larger than 100 residues and allow an accurate description of the protonation states and interactions with nearby water molecules. Despite its low pKa of 4.6 and a large distance of 3.6 Å to the charged Asp189 at the bottom of the S1 pocket, the amino group of aniline becomes protonated, whereas in 2-aminopyridine, the pyridine nitrogen picks up the proton although its amino group is 1.6 Å closer to Asp189. Therefore, apart from charge-charge distances, tautomer stability is decisive for the resulting binding poses, an aspect that is pivotal for predicting correct binding.


    Organizational Affiliation

    Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032, Marburg, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cationic trypsin
A
223Bos taurusMutation(s): 0 
EC: 3.4.21.4
Find proteins for P00760 (Bos taurus)
Go to UniProtKB:  P00760
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
2AP
Query on 2AP

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Download CCD File 
A
2-AMINOPYRIDINE
C5 H7 N2
ICSNLGPSRYBMBD-UHFFFAOYSA-O
 Ligand Interaction
DOD
Query on DOD

Download SDF File 
Download CCD File 
A
DEUTERATED WATER
D2 O
XLYOFNOQVPJJNP-ZSJDYOACSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: NEUTRON DIFFRACTION
  • Resolution: 1.42 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.166 
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
Cootmodel building
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
European Research Council268145-DrugProfilBind

Revision History 

  • Version 1.0: 2017-05-24
    Type: Initial release
  • Version 2.0: 2017-08-23
    Type: Atomic model
  • Version 2.1: 2018-11-14
    Type: Data collection