Solution NMR Structures of Oxidized and Reduced Ehrlichia chaffeensis thioredoxin: NMR-Invisible Structure Owing to Backbone Dynamics

Journal Article · Tue Jan 02 04:00:00 EST 2018 · Acta Crystallographica. Section F, Structural Biology Communications

DOI:https://doi.org/10.1107/S2053230X1701799X· OSTI ID:1415689

Buchko, Garry W.; Hewitt, Stephen N.; Van Voorhis, Wesley C.; Myler, Peter J.

Thioredoxins (Trxs) are small ubiquitous proteins that participate in a diverse variety of redox reactions via the reversible oxidation of two cysteine thiol groups in a structurally conserved active site, CGPC. Here, we describe the NMR solution structures of a Trx from Ehrlichia chaffeensis (Ec-Trx, ECH_0218), the etiological agent responsible for human monocytic ehrlichiosis, in both the oxidized and reduced states. The overall topology of the calculated structures is similar in both redox states and similar to other Trx structures, a five-strand, mixed -sheet (1:3:2:4:5) surrounded by four -helices. Unlike other Trxs studied by NMR in both redox states, the 1H-15N HSQC spectra of reduced Ec-Trx was missing eight amide cross peaks relative to the spectra of oxidized Ec-Trx. These missing amides correspond to residues C32-E39 in the active site containing helix (2) and S72-I75 in a loop near the active site and suggest a substantial change in the backbone dynamics associated with the formation of an intramolecular C32-C35 disulfide bond.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1415689
• Report Number(s): PNNL-SA-126464; 50089; 49703; 49153; 48233; 48683; 453040220
• Journal Information: Acta Crystallographica. Section F, Structural Biology Communications, Journal Name: Acta Crystallographica. Section F, Structural Biology Communications Journal Issue: 1 Vol. 74; ISSN 2053-230X
• Publisher: International Union of Crystallography
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory
NMR spectroscopy
SSGCID
infectious diseases
molecular dynamics
structural biology