6NZB

Crystal structure of E. coli fumarase C S318A variant with closed SS Loop at 1.37 angstrom resolution

Summary for 6NZB

• Entry DOI: 10.2210/pdb6nzb/pdb
• Descriptor: Fumarate hydratase class II, CITRIC ACID (3 entities in total)
• Functional Keywords: fumarase, metabolism, krebs cycle, citrate, lyase
• Biological source: Escherichia coli (strain K12)
• Total number of polymer chains: 2
• Total formula weight: 103215.48

Authors

Weaver, T.M.,May, J.F.,Bhattacharyya, B. (deposition date: 2019-02-13, release date: 2019-09-25, Last modification date: 2023-10-11)

Primary citation

Stuttgen, G.M.,Grosskopf, J.D.,Berger, C.R.,May, J.F.,Bhattacharyya, B.,Weaver, T.M.
Closed fumarase C active-site structures reveal SS Loop residue contribution in catalysis.
Febs Lett., 594:337-357, 2020

PubMed Abstract: Fumarase C (FumC) catalyzes the reversible conversion of fumarate to S-malate. Previous structural investigations within the superfamily have reported a dynamic structural segment, termed the SS Loop. To date, active-site asymmetry has raised the question of how SS Loop placement affects participation of key residues during the reaction. Herein, we report structural and kinetic analyses from Escherichia coli FumC variants to understand the contribution of SS Loop residues S318, K324, and N326. High-resolution X-ray crystallographic results reveal three distinct FumC active-site conformations; disordered-open, ordered-open, and the newly discovered ordered-closed. Surprisingly, each SS Loop variant has unaffected Michaelis constants coupled to reductions in turnover number. Based upon our structural and functional analyses, we propose structural and catalytic roles for each of the aforementioned residues.

PubMed: 31514245
DOI: 10.1002/1873-3468.13603

Experimental method

X-RAY DIFFRACTION (1.37 Å)