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1.C.39.3.3
Complement component C6 of 934 aas and 1 TMS; targets phagocytic and some non phagocytic cells (McCormack et al. 2013).  Expressed constitutively in phagocytes and inducibly in parenchymal tissue-forming cells. It is a transmembrane protein of cytosolic vesicles, derived from multiple organelles that translocate to and fuse with bacterium-containing vesicles. Subsequently, perforin-2 polymerizes and forms large clusters of 100 Å pores in the bacterial surface with perforin-2 cleavage products present in the bacteria. Perforin-2 is also required for the bactericidal activity of reactive oxygen and nitrogen species as well as hydrolytic enzymes (McCormack et al. 2015). Perforin-2 exists in membrane-bound (P2a) and secretory (P2b) isoforms, both present in human macrophages. P2a promotes fusion of vesicles with lysosomes, and may therefore play important roles in immune defense (Xiong et al. 2017). Loss of MPEG1 causes increased susceptibility to microbial infection. MPEG1 expression is upregulated in response to proinflammatory signals such as tumor necrosis factor alpha (TNFα) and lipopolysaccharides (LPS). Furthermore, germline mutations in MPEG1 have been identified in connection with recurrent pulmonary mycobacterial infections. Structural studies on MPEG1 revealed that it can form oligomeric pre-pores and pores. The unusual domain arrangement within the MPEG1 architecture suggests a novel mechanism of pore formation that may have evolved to guard against unwanted lysis of host cells (Bayly-Jones et al. 2020).

Accession Number:P13671
Protein Name:Complement component C6
Length:934
Molecular Weight:104786.00
Species:Homo sapiens (Human) [9606]
Number of TMSs:1
Location1 / Topology2 / Orientation3: Secreted1
Substrate small molecules, large molecules

Cross database links:

Structure:
3T5O   4A5W   4E0S   6H03   6H04     

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MARRSVLYFI LLNALINKGQ ACFCDHYAWT QWTSCSKTCN SGTQSRHRQI VVDKYYQENF 
61:	CEQICSKQET RECNWQRCPI NCLLGDFGPW SDCDPCIEKQ SKVRSVLRPS QFGGQPCTAP 
121:	LVAFQPCIPS KLCKIEEADC KNKFRCDSGR CIARKLECNG ENDCGDNSDE RDCGRTKAVC 
181:	TRKYNPIPSV QLMGNGFHFL AGEPRGEVLD NSFTGGICKT VKSSRTSNPY RVPANLENVG 
241:	FEVQTAEDDL KTDFYKDLTS LGHNENQQGS FSSQGGSSFS VPIFYSSKRS ENINHNSAFK 
301:	QAIQASHKKD SSFIRIHKVM KVLNFTTKAK DLHLSDVFLK ALNHLPLEYN SALYSRIFDD 
361:	FGTHYFTSGS LGGVYDLLYQ FSSEELKNSG LTEEEAKHCV RIETKKRVLF AKKTKVEHRC 
421:	TTNKLSEKHE GSFIQGAEKS ISLIRGGRSE YGAALAWEKG SSGLEEKTFS EWLESVKENP 
481:	AVIDFELAPI VDLVRNIPCA VTKRNNLRKA LQEYAAKFDP CQCAPCPNNG RPTLSGTECL 
541:	CVCQSGTYGE NCEKQSPDYK SNAVDGQWGC WSSWSTCDAT YKRSRTRECN NPAPQRGGKR 
601:	CEGEKRQEED CTFSIMENNG QPCINDDEEM KEVDLPEIEA DSGCPQPVPP ENGFIRNEKQ 
661:	LYLVGEDVEI SCLTGFETVG YQYFRCLPDG TWRQGDVECQ RTECIKPVVQ EVLTITPFQR 
721:	LYRIGESIEL TCPKGFVVAG PSRYTCQGNS WTPPISNSLT CEKDTLTKLK GHCQLGQKQS 
781:	GSECICMSPE EDCSHHSEDL CVFDTDSNDY FTSPACKFLA EKCLNNQQLH FLHIGSCQDG 
841:	RQLEWGLERT RLSSNSTKKE SCGYDTCYDW EKCSASTSKC VCLLPPQCFK GGNQLYCVKM 
901:	GSSTSEKTLN ICEVGTIRCA NRKMEILHPG KCLA