The crystal structure of Clostridium perfringens SleM, a muramidase involved in cortical hydrolysis during spore germination.

Clostridium perfringens spores employ two peptidoglycan lysins to degrade the spore cortex during germination. SleC initiates cortex hydrolysis to generate cortical fragments that are degraded further by the muramidase SleM. Here, we present the crystal structure of the C. perfringens S40 SleM protein at 1.8 Å. SleM comprises an N-terminal catalytic domain that adopts an irregular α/ß-barrel fold that is common to GH25 family lysozymes, plus a C-terminal fibronectin type III domain. The latter is involved in forming the SleM dimer that is evident in both the crystal structure and in solution. A truncated form of SleM that lacks the FnIII domain shows reduced activity against spore sacculi indicating that this domain may have a role in facilitating the position of substrate with respect to the enzyme's active site. Proteins 2016; 84:1681-1689. © 2016 Wiley Periodicals, Inc.

Detection of foot-and-mouth disease viruses from the A/AFRICA/G-I genotype in the Sultanate of Oman.

Rapid identification and characterization of circulating foot-and-mouth disease virus (FMDV) strains is crucial for effective disease control. In Oman, a few serological and molecular studies have been conducted to identify the strains of FMDV responsible for the outbreaks that have been occurring within the country. In this study, 13 oral epithelial tissue samples from cattle were collected from suspected cases of FMD in Ash Sharqiyah North, Al Batinah North, Dhofar and Ad Dhakhyilia governorates of Oman between 2018 and 2021. FMDV RNA was detected in all samples by real-time RT-PCR and viruses were isolated after one- or two-blind passages in the porcine Instituto Biologico-Rim Suino-2 cell line. Antigen capture ELISA characterized all isolates as serotype A and VP1 phylogenetic analysis placed all sequences within a single clade of the G-I genotype within the A/AFRICA topotype. These sequences shared the closest nucleotide identities to viruses circulating in Bahrain in 2021 (93.5% to 99.5%) and Kenya in 2017 (93.4% to 99.1%). To the best of our knowledge, this is the first time that A/AFRICA/G-I viruses have been detected in Oman. Together with the closely related viruses detected recently in Bahrain, these findings reinforce the importance of deploying effective quarantine control measures to minimize the risks of transboundary transmission of FMD associated with the importation of cattle from East Africa.