Elongation of the poly-γ-glutamate tail of F420 requires both domains of the F420:γ-glutamyl ligase (FbiB) of Mycobacterium tuberculosis

Bashiri, Ghader and Mohamed Rehan, Aisyah and Sreebhavan, Sreevalsan and Baker, Heather M. and Baker, Edward N. and Squire, Christopher J. (2016) Elongation of the poly-γ-glutamate tail of F420 requires both domains of the F420:γ-glutamyl ligase (FbiB) of Mycobacterium tuberculosis. Journal of Biological Chemistry, 291 (13). pp. 6882-6894. ISSN 0021-9258 E-ISSN 1083-351X

	PDF - Published Version Restricted to Repository staff only Download (3MB) | Request a copy
	PDF (WOS) - Published Version Restricted to Repository staff only Download (194kB) | Request a copy

Abstract

Cofactor F420 is an electron carrier with a major role in the oxidoreductive reactions of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). A γ-glutamyl ligase catalyzes the final steps of the F420 biosynthesis pathway by successive additions of L-glutamate residues to F420-0, producing a poly-γ-glutamate tail. The enzyme responsible for this reaction in Archaea (CofE) comprises a single domain and produces F420-2 as the major species. The homologous Mtb enzyme, FbiB, is a two-domain protein and produces F420 with predominantly 5-7 L-glutamate residues in the poly-γ-glutamate tail. The N-terminal domain of FbiB is homologous to CofE with an annotated γ-glutamyl ligase activity, whereas the C-terminal domain has sequence similarity to an FMN-dependent family of nitroreductase enzymes. Here we demonstrate that full-length FbiB adds multiple L-glutamate residues to F420-0 in vitro to produce F420-5 after 24 hours; communication between the two domains is critical for full γ-glutamyl ligase activity. We also present crystal structures of the C-terminal domain of FbiB in apo, F420-0 and FMN bound states, displaying distinct sites for F420-0 and FMN ligands that partially overlap. Finally, we discuss the features of a full-length structural model produced by small angle X-ray scattering (SAXS) and its implications for the role of N- and C-terminal domains in catalysis.

Item Type:	Article (Journal)
Additional Information:	4469/50126
Uncontrolled Keywords:	crystal structure; high-performance liquid chromatography (HPLC); mass spectrometry (MS); Mycobacterium tuberculosis; x-ray crystallography; FbiB; cofactor F420; gamma-glutamyl ligase; poly-gamma-glutamate tail
Subjects:	Q Science > Q Science (General)
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Science > Department of Biotechnology
Depositing User:	Mrs Aisyah Mohamed Rehan
Date Deposited:	03 Jun 2016 09:00
Last Modified:	23 Oct 2017 11:37
URI:	http://irep.iium.edu.my/id/eprint/50126

Actions (login required)

View Item