Structure Determination of Mycobacterium tuberculosis Serine Protease Hip1 (Rv2224c)

• Type of Material: Article
• Authors: Jacqueline L. Naffin-Olivos, Brandeis University; Andrew Daab, Brandeis University; Andre White, Brandeis University; Nathan E. Goldfarb, California Health Sciences University; Amy C. Milne, Brandeis University; Dali Liu, Loyola University; Jacqueline Baikovitz, Brandeis University; Ben M. Dunn, University of Florida; Jyothi Rengarajan, Emory University; Gregory A. Petsko, Weill Cornell Medical College; Dagmar Ringe, Brandeis University
• Language: English
• Date: 2017-05-02
• Publisher: American Chemical Society
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2017 American Chemical Society.
• Final Published Version (URL): http://dx.doi.org/10.1021/acs.biochem.6b01066
• Title of Journal or Parent Work: Biochemistry
• ISSN: 0006-2960
• Volume: 56
• Issue: 17
• Start Page: 2304
• End Page: 2314
• Grant/Funding Information: This work was supported by funds from National Institutes of Health grants R00TW008043 and 5R01AI083366 (to J.R.), GM 32415 (to G.A.P. and D.R.), and R37AI28571 (to B.M.D.).
• Keywords: Life Sciences & Biomedicine; PROLYL AMINOPEPTIDASE; ALPHA/BETA-HYDROLASE FOLD; RESPONSES; ENZYMES; MODEL; GEOMETRY; Science & Technology; CRYSTAL-STRUCTURE; MECHANISM; Biochemistry & Molecular Biology; SURVIVAL; ACTIVATION
• Research Categories: Chemistry, Biochemistry

Abstract

The Mycobacterium tuberculosis (Mtb) serine protease Hip1 (hydrolase important for pathogenesis; Rv2224c) promotes tuberculosis (TB) pathogenesis by impairing host immune responses through proteolysis of a protein substrate, Mtb GroEL2. The cell surface localization of Hip1 and its immunomodulatory functions make Hip1 a good drug target for new adjunctive immune therapies for TB. Here, we report the crystal structure of Hip1 to a resolution of 2.6 Å and the kinetic studies of the enzyme against model substrates and the protein GroEL2. The structure shows a two-domain protein, one of which contains the catalytic residues that are the signature of a serine protease. Surprisingly, a threonine is located within the active site close enough to hydrogen bond with the catalytic residues Asp463 and His490. Mutation of this residue, Thr466, to alanine established its importance for function. Our studies provide insights into the structure of a member of a novel family of proteases. Knowledge of the Hip1 structure will aid in designing inhibitors that could block Hip1 activity.