The Origins of Specificity in the Microcin-Processing Protease TldD/E

DOI: 10.1016/j.str.2017.08.006

Authors: Dmitry Ghilarov (Skolkovo Institute of Science and Technology) , Marina Serebryakova (Institute of Gene Biology of the Russian Academy of Sciences; Lomonosov Moscow State University) , Clare E. M. Stevenson (John Innes Centre) , Stephen J. Hearnshaw (John Innes Centre) , Dmitry Volkov (Lomonosov Moscow State University) , Anthony Maxwell (John Innes Centre) , David M. Lawson (John Innes Centre) , Konstantin Severinov (Skolkovo Institute of Science and Technology; Bionano Institute, Peter the Great Saint Petersburg State Polytechnical University; The State University of New Jersey)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Structure

State: Published (Approved)
Published: September 2017
Diamond Proposal Number(s): 9475

Abstract: TldD and TldE proteins are involved in the biosynthesis of microcin B17 (MccB17), an Escherichia coli thiazole/oxazole-modified peptide toxin targeting DNA gyrase. Using a combination of biochemical and crystallographic methods we show that E. coli TldD and TldE interact to form a heterodimeric metalloprotease. TldD/E cleaves the N-terminal leader sequence from the modified MccB17 precursor peptide, to yield mature antibiotic, while it has no effect on the unmodified peptide. Both proteins are essential for the activity; however, only the TldD subunit forms a novel metal-containing active site within the hollow core of the heterodimer. Peptide substrates are bound in a sequence-independent manner through β sheet interactions with TldD and are likely cleaved via a thermolysin-type mechanism. We suggest that TldD/E acts as a “molecular pencil sharpener”: unfolded polypeptides are fed through a narrow channel into the active site and processively truncated through the cleavage of short peptides from the N-terminal end.

Journal Keywords: microcin B17; DNA gyrase; metalloprotease; CcdAB; X-ray crystallography; toxin-antitoxin; ribosomally synthesized modified peptides; RiPP; peptidase

Subject Areas: Biology and Bio-materials, Chemistry, Medicine


Instruments: I02-Macromolecular Crystallography , I03-Macromolecular Crystallography , I04-1-Macromolecular Crystallography (fixed wavelength)

Other Facilities: No

Added On: 23/09/2017 13:27

Documents:
1-s2.0-S0969212617302599-main.pdf

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