ID   OMCA_CHLTH              Reviewed;          88 AA.
AC   P0DJI1; P18585; P21356;
DT   13-JUN-2012, integrated into UniProtKB/Swiss-Prot.
DT   13-JUN-2012, sequence version 1.
DT   25-MAY-2022, entry version 25.
DE   RecName: Full=Small cysteine-rich outer membrane protein OmcA;
DE            Short=Small-CRP;
DE   AltName: Full=9 kDa cysteine-rich lipoprotein;
DE            Short=9kDa-CRP;
DE   Flags: Precursor;
GN   Name=omcA; Synonyms=omp3;
OS   Chlamydia trachomatis.
OC   Bacteria; Chlamydiae; Chlamydiales; Chlamydiaceae;
OC   Chlamydia/Chlamydophila group; Chlamydia.
OX   NCBI_TaxID=813;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=L1/440/LN;
RX   PubMed=2332164; DOI=10.1016/0378-1119(90)90500-q;
RA   Lambden P.R., Everson J.S., Ward M.E., Clarke I.N.;
RT   "Sulfur-rich proteins of Chlamydia trachomatis: developmentally regulated
RT   transcription of polycistronic mRNA from tandem promoters.";
RL   Gene 87:105-112(1990).
CC   -!- FUNCTION: In elementary bodies (EBs, the infectious stage, which is
CC       able to survive outside the host cell) provides the structural
CC       integrity of the outer envelope through disulfide cross-links with the
CC       large cysteine-rich periplasmic protein and the major outer membrane
CC       porin. It has been described in publications as the Sarkosyl-insoluble
CC       COMC (Chlamydia outer membrane complex), and serves as the functional
CC       equivalent of peptidoglycan (By similarity). {ECO:0000250}.
CC   -!- SUBUNIT: Part of a disulfide cross-linked outer membrane complex (COMC)
CC       composed of the major outer membrane porin (MOMP), the small cysteine-
CC       rich protein (OmcA) and the large cysteine-rich periplasmic protein
CC       (OmcB). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Cell outer membrane {ECO:0000305}; Lipid-anchor
CC       {ECO:0000255|PROSITE-ProRule:PRU00303}. Note=The protein moiety
CC       probably penetrates into the periplasm.
CC   -!- DEVELOPMENTAL STAGE: It is present but the disulfide bonds are reduced
CC       in reticulate bodies (RBs).
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DR   EMBL; M35148; AAA23118.1; -; Genomic_DNA.
DR   PIR; JQ0514; JQ0514.
DR   RefSeq; WP_009873814.1; NZ_NHBA01000001.1.
DR   AlphaFoldDB; P0DJI1; -.
DR   OMA; PDGRCKQ; -.
DR   GO; GO:0009279; C:cell outer membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0005201; F:extracellular matrix structural constituent; IEA:InterPro.
DR   GO; GO:0008360; P:regulation of cell shape; IEA:UniProtKB-KW.
DR   InterPro; IPR003517; Cys-rich_OMP3_Chlamydia.
DR   Pfam; PF03503; Chlam_OMP3; 1.
DR   PRINTS; PR01335; CHLAMIDIAOM3.
DR   PROSITE; PS51257; PROKAR_LIPOPROTEIN; 1.
PE   2: Evidence at transcript level;
KW   Cell outer membrane; Cell shape; Disulfide bond; Lipoprotein; Membrane;
KW   Palmitate; Signal.
FT   SIGNAL          1..18
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00303"
FT   CHAIN           19..88
FT                   /note="Small cysteine-rich outer membrane protein OmcA"
FT                   /id="PRO_0000018156"
FT   REGION          67..88
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   LIPID           19
FT                   /note="N-palmitoyl cysteine"
FT                   /evidence="ECO:0000305"
FT   LIPID           19
FT                   /note="S-diacylglycerol cysteine"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   88 AA;  9279 MW;  D35B0584EEC7DA1B CRC64;
     MKKTALLAAL CSVVSLSSCC RIVDCCFEDP CAPIQCSPCE SKKKDVDGGC NSCNGYVPAC
     KPCGGDTHQD AEHGPQAREI PVDGKCRQ