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#pseudomurein

3 public questions tagged with this topic.

Microbial Physiology

Which archaeal species contains pseudomurein in its cell wall?

Distribution of pseudomurein within Archaea is limited to certain methanogenic euryarchaeota that build rigid wall sacculus, whereas many other archaea rely solely on proteinaceous S-layers. Methanobrevibacter species, including human commensal Methanobrevibacter smithii and rumen isolate Methanobrevibacter ruminantium within order Methanobacteriales, synthesize pseudomurein composed of N-acetylglucosamine and N-acetyltalosaminuronic acid linked beta-1,3 and crosslinked with tetrapeptides containing L-amino acids. Related genera like Methanobacterium and Methanothermobacter share this trait, d

Ref: Kandler, Microbiol Sci 1982, Pseudomurein Distribution; Doddema et al., Int J Syst Bacteriol 1982, Methanobrevibacter.

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Microbial Physiology

Which glycosidic bond is found in the pseudomurein of archaea?

Glycosidic bond specificity determines susceptibility to host defenses and bacteriophages. Bacterial peptidoglycan uses beta-1,4 linkages between N-acetylglucosamine and N-acetylmuramic acid, a substrate efficiently cleaved by hen egg white lysozyme and human lysozyme in tears and mucus, which hydrolyzes between C1 of MurNAc and C4 of GlcNAc. Archaeal pseudomurein in methanogens such as Methanobacterium and Methanobrevibacter employs beta-1,3 linkage between N-acetylglucosamine and N-acetyltalosaminuronic acid. This change in linkage position alters orientation of sugar residues and active sit

Ref: Sekh et al., Extremophiles 2020, Pseudomurein Linkages; Leahy et al., Front Microbiol 2020, Archaeal Wall.

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Microbial Physiology

In the pseudomurein layer, which sugar replaces N-acetylmuramic acid (NAM) found in bacterial peptidoglycan?

Pseudomurein represents fascinating case of convergent evolution where archaeal methanogens assemble wall polymer with superficial resemblance to bacterial peptidoglycan but distinct sugar composition rendering it insensitive to many antibacterial agents. In bacterial murein, alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) linked beta-1,4 carry lactyl ether with short peptide containing D-amino acids. Archaeal pseudomurein replaces NAM with N-acetyl-D-talosaminuronic acid, abbreviated NAT, which is N-acetylglucosamine epimer bearing carboxyl group at different position and

Ref: Kandler & Hippe, Arch Microbiol 1977, Pseudomurein Sacculus; Evren et al., J Bacteriol 2022, Pseudomurein Chemistry.

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