Crystal structure of TsaC

Experimental Data Snapshot

  • Resolution: 2.18 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.209 

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The NADH recycling enzymes TsaC and TsaD regenerate reducing equivalents for Rieske oxygenase chemistry.

Tian, J.Boggs, D.G.Donnan, P.H.Barroso, G.T.Garcia, A.A.Dowling, D.P.Buss, J.A.Bridwell-Rabb, J.

(2023) J Biol Chem 299: 105222-105222

  • DOI: https://doi.org/10.1016/j.jbc.2023.105222
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Many microorganisms use both biological and nonbiological molecules as sources of carbon and energy. This resourcefulness means that some microorganisms have mechanisms to assimilate pollutants found in the environment. One such organism is Comamonas testosteroni, which metabolizes 4-methylbenzenesulfonate and 4-methylbenzoate using the TsaMBCD pathway. TsaM is a Rieske oxygenase, which in concert with the reductase TsaB consumes a molar equivalent of NADH. Following this step, the annotated short-chain dehydrogenase/reductase and aldehyde dehydrogenase enzymes TsaC and TsaD each regenerate a molar equivalent of NADH. This co-occurrence ameliorates the need for stoichiometric addition of reducing equivalents and thus represents an attractive strategy for integration of Rieske oxygenase chemistry into biocatalytic applications. Therefore, in this work, to overcome the lack of information regarding NADH recycling enzymes that function in partnership with Rieske non-heme iron oxygenases (Rieske oxygenases), we solved the X-ray crystal structure of TsaC to a resolution of 2.18 Å. Using this structure, a series of substrate analog and protein variant combination reactions, and differential scanning fluorimetry experiments, we identified active site features involved in binding NAD + and controlling substrate specificity. Further in vitro enzyme cascade experiments demonstrated the efficient TsaC- and TsaD-mediated regeneration of NADH to support Rieske oxygenase chemistry. Finally, through in-depth bioinformatic analyses, we illustrate the widespread co-occurrence of Rieske oxygenases with TsaC-like enzymes. This work thus demonstrates the utility of these NADH recycling enzymes and identifies a library of short-chain dehydrogenase/reductase enzyme prospects that can be used in Rieske oxygenase pathways for in situ regeneration of NADH.

  • Organizational Affiliation

    Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
4-formylbenzenesulfonate dehydrogenase TsaC
A, B
272Comamonas testosteroniMutation(s): 0 
Gene Names: tsaC1tsaCtsaC2
Find proteins for P94681 (Comamonas testosteroni)
Explore P94681 
Go to UniProtKB:  P94681
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP94681
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.18 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.209 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 115.7α = 90
b = 115.7β = 90
c = 66.3γ = 120
Software Package:
Software NamePurpose
XDSdata reduction
XDSdata scaling
Cootmodel building

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesR35 GM138271

Revision History  (Full details and data files)

  • Version 1.0: 2023-09-20
    Type: Initial release
  • Version 1.1: 2023-10-25
    Changes: Database references