3oxh

Publication Abstract from PubMed

Mycobacterium tuberculosis protein Rv0577 is a prominent antigen in tuberculosis patients, the component responsible for neutral red staining of virulent strains of M. tuberculosis, a putative component in a methylglyoxal detoxification pathway, and an agonist of toll-like receptor 2. It also has an amino acid sequence that is 36% identical to that of Streptomyces coelicolor AfsK-binding protein A (KbpA), a component in the complex secondary metabolite pathways in the Streptomyces genus. To gain insight into the biological function of Rv0577 and the family of KpbA kinase regulators, the crystal structure for Rv0577 was determined to a resolution of 1.75 A, binding properties with neutral red and deoxyadenosine were surveyed, backbone dynamics were measured, and thermal stability was assayed by circular dichroism spectroscopy. The protein is composed of four approximate repeats with a betaalphabetabetabeta topology arranged radially in consecutive pairs to form two continuous eight-strand beta-sheets capped on both ends with an alpha-helix. The two beta-sheets intersect in the center at roughly a right angle and form two asymmetric deep "saddles" that may serve to bind ligands. Nuclear magnetic resonance chemical shift perturbation experiments show that neutral red and deoxyadenosine bind to Rv0577. Binding to deoxyadenosine is weaker with an estimated dissociation constants of 4.1 +/- 0.3 mM for saddle 1. Heteronuclear steady-state {1H}-15N nuclear Overhauser effect, T1, and T2 values were generally uniform throughout the sequence with only a few modest pockets of differences. Circular dichroism spectroscopy characterization of the thermal stability of Rv0577 indicated irreversible unfolding upon heating with an estimated melting temperature of 56 degrees C.

Structural and Biophysical Characterization of the Mycobacterium tuberculosis Protein Rv0577, a Protein Associated with Neutral Red Staining of Virulent Tuberculosis Strains and Homologue of the Streptomyces coelicolor Protein KbpA.,Buchko GW, Echols N, Flynn EM, Ng HL, Stephenson S, Kim HB, Myler PJ, Terwilliger TC, Alber T, Kim CY Biochemistry. 2017 Aug 1;56(30):4015-4027. doi: 10.1021/acs.biochem.7b00511. Epub, 2017 Jul 25. PMID:28692281^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.