Structural characterization of an S8 protease from Fervidobacterium pennivorans reveals a unique tyrosine-rich β-hairpin

DOI: 10.1016/j.enzmictec.2026.110904

Authors: Michail W. Kruger (University of the Free State) , Gabriela C. Schröder (University of the Free State) , Rubén Javier-López (University of Bergen) , Carmien Tolmie (University of the Free State) , Ana C. Ebrecht (University of the Free State) , Jennifer A. Littlechild (University of Exeter) , Jean Armengaud (Université Paris Saclay, CEA, INRAE) , Nils-Kåre Birkeland (University of Bergen) , Diederik J. Opperman (University of the Free State)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Enzyme And Microbial Technology , VOL 199

State: Published (Approved)
Published: August 2026
Diamond Proposal Number(s): 28402 , 35088

Abstract: Keratin is an abundant structural fibrous protein and extremely recalcitrant biopolymer. β-Keratin is the major constituent of feathers, which, due to the widespread poultry industry, has become a major waste product. Biotechnological upcycling of feather waste has gained interest as various bacteria and fungi capable of degrading keratin have been isolated. These microorganisms produce proteases, termed keratinases, responsible for the enzymatic hydrolysis of keratin. The structural properties that confer keratinolytic activity to proteases are, however, not well understood. Here, we investigated the structure-function relationship of a subtilisin-like S8 endopeptidase (FerB) from the thermophile Fervidobacterium pennivorans strain T. FerB was crystallized and its structure solved to 1.5 Å resolution, revealing an auto-processed state where the pro-peptide domain is non-covalently attached to the catalytic domain. The carboxyl group of the scissile peptide bond is coordinated in the active site within hydrogen bonding distance of the catalytic triad’s serine residue. Unlike fervidolysin, no β-sandwich domains are present. However, a tyrosine-rich β-hairpin structure is found in the corresponding position within the FerB structure. Deletion of the β-hairpin reduced the protein’s integrity and keratinase activity.

Journal Keywords: Keratinase; Protease; Subtilisin; β-keratin; Fervidolysin; FerB; Fervidobacterium pennivorans

Diamond Keywords: Enzymes; Bacteria

Subject Areas: Biology and Bio-materials, Chemistry


Instruments: I04-Macromolecular Crystallography

Added On: 27/05/2026 08:36

Documents:
1-s2.0-S0141022926000876-main.pdf

Discipline Tags:

Biotechnology Biochemistry Chemistry Structural biology Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)