@article{10902/27795,
year = {2023},
url = {https://hdl.handle.net/10902/27795},
abstract = {The steep increase in nontuberculous mycobacteria (NTM) infections makes understanding their unique physiology an urgent health priority. NTM synthesize two polysaccharides proposed to modulate fatty acid metabolism: the ubiquitous 6-O-methylglucose lipopolysaccharide, and the 3-O-methylmannose polysaccharide (MMP) so far detected in rapidly growing mycobacteria. The recent identification of a unique MMP methyltransferase implicated the adjacent genes in MMP biosynthesis. We report a wide distribution of this gene cluster in NTM, including slowly growing mycobacteria such as Mycobacterium avium, which we reveal to produce MMP. Using a combination of MMP purification and chemoenzymatic syntheses of intermediates, we identified the biosynthetic mechanism of MMP, relying on two enzymes that we characterized biochemically and structurally: a previously undescribed ∝-endomannosidase that hydrolyses MMP into defined-sized mannoligosaccharides that prime the elongation of new daughter MMP chains by a rare ∝-(1→4)-mannosyltransferase. Therefore, MMP biogenesis occurs through a partially conservative replication mechanism, whose disruption affected mycobacterial growth rate at low temperature.},
organization = {Acknowledgements: This work was funded by Portuguese national funds via FCT—Fundação para a Ciência e a Tecnologia through projects PTDC/BIA-MIC/0122/2021, UIDB/04539/2020, UIDP/04539/2020 and LA/P/0058/2020; through PhD Fellowship SFRH/BD/101191/2014 (to M.C.); through contract POCI-01-0145-FEDER-029221 (to A. M.); through contract DL 57/2016/CP1355/CT0011 (to J.R.-R.) and by the European Social Fund through Programa Operacional Capital Humano in the form of Postdoctoral Fellowship SFRH/BPD/108004/2015 (to J.R.-R.) and by the European Regional Development Fund (FEDER) through the COMPETE 2020-Operational Programme for Competitiveness and Internationalization (POCI), Portugal 2020 in the form of grant POCI-01-0145-FEDER-029221, and the National Mass Spectrometry Network (RNEM) under the contract POCI-01-0145-FEDER-402-022125 (ref.: ROTEIRO/0028/2013). M.R.V. acknowledges MostMicro Research Unit, financially supported by LISBOA-01-0145-FEDER-007660 funded by FEDER funds through COMPETE2020 (POCI) and by national funds through FCT. The NMR data was acquired at CERMAX, ITQB-NOVA, Oeiras, Portugal with equipment funded by FCT, project AAC 01/SAICT/2016. We thank Igor Tiago (Centre for Functional Ecology, University of Coimbra) for support with computation and bioinformatic analyses. We thank ALBA Synchrotron (Cerdanyola del Vallès, Spain) and the European Synchrotron Radiation Facility (Grenoble, France) for provision of synchrotron radiation facilities, and their staff for help with data collection. The support of the X-ray Crystallography scientific platform of i3S (Porto, Portugal) is also acknowledged.},
publisher = {Nature},
publisher = {Communications biology, 2023, 6(1), 108},
title = {Self-recycling and partially conservative replication of mycobacterial methylmannose polysaccharides},
author = {Maranha, Ana and Costa, Mafalda and Ripoll Rozada, Jorge and Manso, José A and Miranda, Vanessa and Mendes, Vera M and Manadas, Bruno and Macedo-Ribeiro, Sandra and Ventura, M Rita and Pereira, Pedro José Barbosa and Empadinhas, Nuno},
}