7RW3

E. coli cysteine desulfurase SufS N99D

Summary for 7RW3

• Entry DOI: 10.2210/pdb7rw3/pdb
• Descriptor: Cysteine desulfurase, PYRIDOXAL-5'-PHOSPHATE (3 entities in total)
• Functional Keywords: cysteine desulfurase, sufs, plp, transferase
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 44760.79

Authors

Dunkle, J.A.,Gogar, R.,Frantom, P.A. (deposition date: 2021-08-19, release date: 2023-01-25, Last modification date: 2023-11-15)

Primary citation

Gogar, R.K.,Carroll, F.,Conte, J.V.,Nasef, M.,Dunkle, J.A.,Frantom, P.A.
The beta-latch structural element of the SufS cysteine desulfurase mediates active site accessibility and SufE transpersulfurase positioning.
J.Biol.Chem., 299:102966-102966, 2023

PubMed Abstract: Under oxidative stress and iron starvation conditions, Escherichia coli uses the Suf pathway to assemble iron-sulfur clusters. The Suf pathway mobilizes sulfur via SufS, a type II cysteine desulfurase. SufS is a pyridoxal-5'-phosphate-dependent enzyme that uses cysteine to generate alanine and an active-site persulfide (C-S-S). The SufS persulfide is protected from external oxidants/reductants and requires the transpersulfurase, SufE, to accept the persulfide to complete the SufS catalytic cycle. Recent reports on SufS identified a conserved "β-latch" structural element that includes the α helix, a glycine-rich loop, a β-hairpin, and a cis-proline residue. To identify a functional role for the β-latch, we used site-directed mutagenesis to obtain the N99D and N99A SufS variants. N99 is a conserved residue that connects the α helix to the backbone of the glycine-rich loop via hydrogen bonds. Our x-ray crystal structures for N99A and N99D SufS show a distorted beta-hairpin and glycine-rich loop, respectively, along with changes in the dimer geometry. The structural disruption of the N99 variants allowed the external reductant TCEP to react with the active-site C364-persulfide intermediate to complete the SufS catalytic cycle in the absence of SufE. The substitutions also appear to disrupt formation of a high-affinity, close approach SufS-SufE complex as measured with fluorescence polarization. Collectively, these findings demonstrate that the β-latch does not affect the chemistry of persulfide formation but does protect it from undesired reductants. The data also indicate the β-latch plays an unexpected role in forming a close approach SufS-SufE complex to promote persulfide transfer.

PubMed: 36736428
DOI: 10.1016/j.jbc.2023.102966

Experimental method

X-RAY DIFFRACTION (2.3 Å)