6MVZ

Mle-Phe-Mle-Phe. Linear precursor of pseudoxylallemycin A.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 0.83 Å
  • R-Value Observed: 0.068 

wwPDB Validation   3D Report Full Report


This is version 1.0 of the entry. See complete history


Literature

Investigations of the key macrolactamisation step in the synthesis of cyclic tetrapeptide pseudoxylallemycin A.

Cameron, A.J.Squire, C.J.Gerenton, A.Stubbing, L.A.Harris, P.W.R.Brimble, M.A.

(2019) Org Biomol Chem 17: 3902-3913

  • DOI: 10.1039/c9ob00227h
  • Primary Citation of Related Structures:  
    6MVZ, 6MW0, 6MW1, 6MW2

  • PubMed Abstract: 
  • The total synthesis and structural confirmation of naturally occurring all l-cyclic tetrapeptide pseudoxylallemycin A is reported. X-ray crystallography revealed that the linear precursor adopted an all-trans (ttt) extended linear conformation, while its cyclic derivative adopts a trans,cis,trans,cis (tctc) conformation ...

    The total synthesis and structural confirmation of naturally occurring all l-cyclic tetrapeptide pseudoxylallemycin A is reported. X-ray crystallography revealed that the linear precursor adopted an all-trans (ttt) extended linear conformation, while its cyclic derivative adopts a trans,cis,trans,cis (tctc) conformation. Two kinetically favoured cyclic conformers prone to hydrolysis initially formed rapidly during cyclisation, with subsequent conversion to the thermodynamically stable tctc macrocycle taking place slowly. We postulate the initial unstable cyclic product undergoes an unprecedented nucleophilic ring opening with either the T3P or PyAOP by-products to give the linear ttt structure as a reactivated species and through a series of equilibria is slowly consumed by cyclisation to the thermodynamic product pseudoxylallemycin A. Consumption of the reactivated species by formation of pseudoxylallemycin A requires a trans-cis isomerism to occur and necessitates moderately increased reaction temperatures. Cyclisation with T3P was found to provide the greatest stereoretention. Synthesis and X-ray crystallography of the C-terminal epimer demonstrated its cyclisation to be kinetically favoured and to proceed without epimerisation despite also bearing an all-trans backbone.


    Organizational Affiliation

    School of Chemical Sciences, The University of Auckland, 23 Symonds St, Auckland 1010, New Zealand. m.brimble@auckland.ac.nz.



Macromolecules

Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Linear precursor of pseudoxylallemycin AA4XylariaMutation(s): 0 
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
TFA
Query on TFA

Download Ideal Coordinates CCD File 
B [auth A]trifluoroacetic acid
C2 H F3 O2
DTQVDTLACAAQTR-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MLE
Query on MLE
A L-PEPTIDE LINKINGC7 H15 N O2LEU
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 0.83 Å
  • R-Value Observed: 0.068 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 8.255α = 90
b = 19.173β = 90
c = 23.446γ = 90
Software Package:
Software NamePurpose
SHELXLrefinement
XDSdata reduction
Aimlessdata scaling
SHELXSphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2019-09-11
    Type: Initial release