6M8F

Engineered sperm whale myoglobin-based carbene transferase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.10 Å
  • R-Value Free: 0.146 
  • R-Value Work: 0.126 
  • R-Value Observed: 0.127 

Starting Model: experimental
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This is version 2.1 of the entry. See complete history


Literature

Origin of high stereocontrol in olefin cyclopropanation catalyzed by an engineered carbene transferase.

Tinoco, A.Wei, Y.Bacik, J.P.Carminati, D.M.Moore, E.J.Ando, N.Zhang, Y.Fasan, R.

(2019) ACS Catal 9: 1514-1524

  • DOI: https://doi.org/10.1021/acscatal.8b04073
  • Primary Citation of Related Structures:  
    6M8F

  • PubMed Abstract: 

    Recent advances in metalloprotein engineering have led to the development of a myoglobin-based catalyst, Mb(H64V,V68A), capable of promoting the cyclopropanation of vinylarenes with high efficiency and high diastereo- and enantioselectivity. Whereas many enzymes evolved in nature often exhibit catalytic proficiency and exquisite stereoselectivity, how these features are achieved for a non-natural reaction has remained unclear. In this work, the structural determinants responsible for chiral induction and high stereocontrol in Mb(H64V,V68A)-catalyzed cyclopropanation were investigated via a combination of crystallographic, computational (DFT), and structure-activity analyses. Our results show the importance of steric complementarity and non-covalent interactions involving first-sphere active site residues, heme-carbene, and the olefin substrate, in dictating the stereochemical outcome of the cyclopropanation reaction. High stereocontrol is achieved through two major mechanisms. First, by enforcing a specific conformation of the heme-bound carbene within the active site. Second, by controlling the geometry of attack of the olefin on the carbene via steric occlusion, attractive van der Waals forces and protein-mediated π-π interactions with the olefin substrate. These insights could be leveraged to expand the substrate scope of the myoglobin-based cyclopropanation catalyst toward non-activated olefins and to increase its cyclopropanation activity in the presence of a bulky α-diazo-ester. This work sheds first light into the origin of enzyme-catalyzed enantioselective cyclopropanation, furnishing a mechanistic framework for both understanding the reactivity of current systems and guiding the future development of biological catalysts for this class of synthetically important, abiotic transformations.


  • Organizational Affiliation

    Department of Chemistry, University of Rochester, Rochester, NY 14627, United States.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Myoglobin154Physeter catodonMutation(s): 0 
Gene Names: MB
EC: 1.11.1 (UniProt), 1.7 (UniProt)
UniProt
Find proteins for P02185 (Physeter macrocephalus)
Explore P02185 
Go to UniProtKB:  P02185
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02185
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
beta-D-fructofuranose-(2-1)-alpha-D-glucopyranose
B
2N/A
Glycosylation Resources
GlyTouCan:  G05551OP
GlyCosmos:  G05551OP
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.10 Å
  • R-Value Free: 0.146 
  • R-Value Work: 0.126 
  • R-Value Observed: 0.127 
  • Space Group: P 6
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 90.78α = 90
b = 90.78β = 90
c = 45.58γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
MOSFLMdata reduction
SCALAdata scaling
PHENIXphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2019-01-23
    Type: Initial release
  • Version 1.1: 2019-06-12
    Changes: Data collection, Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Non-polymer description, Structure summary
  • Version 2.1: 2023-10-11
    Changes: Data collection, Database references, Refinement description, Structure summary