These are all Streptococcus species, most Leuconostoc, Weissella, and Oenococcus species, and some Lactococcus species .
PsB are also found among several species of other genera (in particular, Enterococcus faecalis).
All PsB have peptidoglycan (basis of their cell membrane) containing interpeptide bridges of type (L-Ala)-(L-Ala) and/or (L-Ser)-(L-Ala).
This peptidoglycan is similar to peptidoglycan of pathogenic bacterium Streptococcus pyogenes.
Within YN-model of psoriasis pathogenesis, it is assumed that antigen that causes inadequate response of skin immune system originates from fragments of interpeptide bridges of this particular peptidoglycan. And this antigen enters skin inside blood neutrophils, which, firstly, endocytose bacterial products in blood, secondly, are attracted to inflamed skin and, thirdly, can undergo NETosis (self-destruction) in inflamed skin (Peslyak & Korotky 2020).
Formation of these bridges in peptidoglycan is due to presence of enzymes such as murM and murN.
The murM is enzyme that provides addition of serine/alanine (first amino acid starting from Lys) during formation of interpeptide bridge in peptidoglycan. In absence of this enzyme, there will be almost no bridges. What exactly is added (serine or alanine) depends on allele of murM gene.
The murN is enzyme that provides addition of alanine (second amino acid starting from Lys) during formation of interpeptide bridge in peptidoglycan.
In absence of this enzyme, bridge will be one amino acid long.
In different bacteria, formation of interpeptide bridges is provided by different murMN genes (Peslyak & Korotky 2020).
KEGG database identifies all bacterial species (among those included in this database) that have genes that ensure secretion of both enzymes, i.e. both murM and murN types.
Arthrobacter sp.PGP41
Enterococcus faecalis
Enterococcus silesiacus
Eubacterium sulci
Furfurilactobacillus rossiae L1
Lactococcus carnosus
Lactococcus formosensis
Lactococcus garvieae
Lactococcus petauri
Lactococcus piscium
Lactococcus raffinolactis
Leuconostoc carnosum
Leuconostoc citreum
Leuconostoc garlicum
Leuconostoc gasicomitatum
Leuconostoc gelidum
Leuconostoc kimchii
Leuconostoc koreense
Leuconostoc lactis
Leuconostoc mesenteroides
Leuconostoc pseudomesenteroides
Leuconostoc sp.C2
Melissococcus plutonius
Oenococcus oeni
Oenococcus sicerae
Oenococcus sp.UCMA16435
Pseudarthrobacter psychrotolerans
Pseudarthrobacter sulfonivorans
Weissella ceti
Weissella cibaria
Weissella coleopterorum
Weissella diestrammenae
Weissella hellenica
Weissella jogaejeotgali
Weissella koreensis
Weissella paramesenteroides
Weissella soli
Weissella tructae
Weissella viridescens
This list was compiled as of April 3, 2025. It is updated as KEGG database is replenished and refined.