Biology:SecY protein
| SecY protein/Sec61α | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 Structure of a protein-conducting channel.[1] | |||||||||
| Identifiers | |||||||||
| Symbol | SecY | ||||||||
| Pfam | PF00344 | ||||||||
| InterPro | IPR002208 | ||||||||
| PROSITE | PDOC00612 | ||||||||
| SCOP2 | 1rh5 / SCOPe / SUPFAM | ||||||||
| TCDB | 3.A.5 | ||||||||
| OPM superfamily | 19 | ||||||||
| OPM protein | 1rh5 | ||||||||
| Membranome | 165 | ||||||||
| |||||||||
The SecY protein is the main transmembrane subunit of the bacterial Sec export pathway and of a protein-secreting ATPase complex, also known as a SecYEG translocon. Homologs of the SecYEG complex are found in eukaryotes and in archaea, where the subunit is known as Sec61α.[2]
Secretion of some proteins carrying a signal-peptide across the inner membrane in Gram-negative bacteria occurs via the preprotein translocase pathway. Proteins are produced in the cytoplasm as precursors, and require a chaperone subunit to direct them to the translocase component within the membrane.[3] From there, the mature proteins are either targeted to the outer membrane or remain as periplasmic proteins. The translocase protein subunits are encoded on the bacterial chromosome.
The translocase pathway comprises 7 proteins, including a chaperone protein (SecB), an ATPase (SecA), an integral membrane complex (SecY, SecE, and SecG), and two additional membrane proteins that promote the release of the mature peptide into the periplasm (SecD and SecF).[3] The chaperone protein SecB[4] is a highly acidic homotetrameric protein that exists as a "dimer of dimers" in the bacterial cytoplasm. SecB maintains preproteins in an unfolded state after translation and targets these to the peripheral membrane protein ATPase SecA for secretion.[5]
Cytoplasmic regions 2 and 3, and TM domains 1, 2, 4, 5, 7, and 10 are well conserved: the conserved cytoplasmic regions are believed to interact with cytoplasmic secretion factors, while the TM domains may participate in protein export.[6] SecY is also encoded in the chloroplast genome of some algae where it could be involved in a prokaryotic-like protein export system across the two membranes of the chloroplast endoplasmic reticulum (CER) which is present in chromophyte and cryptophyte algae.[7]
Subfamilies
Human proteins containing this domain
SEC61A1; SEC61A2;
See also
References
- ↑ "X-ray structure of a protein-conducting channel". Nature 427 (6969): 36–44. January 2004. doi:10.1038/nature02218. PMID 14661030. Bibcode: 2004Natur.427...36B.
- ↑ "Presence of a gene in the archaebacterium Methanococcus vannielii homologous to secY of eubacteria". Biochimie 73 (6): 683–8. June 1991. doi:10.1016/0300-9084(91)90048-6. PMID 1764515.
- ↑ 3.0 3.1 "The sec and prl genes of Escherichia coli". Journal of Bioenergetics and Biomembranes 22 (3): 291–310. June 1990. doi:10.1007/BF00763169. PMID 2202721.
- ↑ "SecB, a molecular chaperone with two faces". Trends in Microbiology 9 (5): 193–6. May 2001. doi:10.1016/S0966-842X(01)01980-1. PMID 11336818. https://pure.rug.nl/ws/files/3619679/2001TrendsMicrobiolDriessen.pdf.
- ↑ "Effects of pre-protein overexpression on SecB synthesis in Escherichia coli". FEMS Microbiology Letters 176 (1): 219–27. July 1999. doi:10.1016/s0378-1097(99)00239-6. PMID 10418149.
- ↑ "Isolation of a secY homologue from Bacillus subtilis: evidence for a common protein export pathway in eubacteria". Molecular Microbiology 4 (2): 305–14. February 1990. doi:10.1111/j.1365-2958.1990.tb00597.x. PMID 2110998.
- ↑ "A secY homologue is found in the plastid genome of Cryptomonas phi". FEBS Letters 298 (1): 93–6. February 1992. doi:10.1016/0014-5793(92)80029-G. PMID 1544427.
Further reading
- Lewis, AJO; Hegde, RS (15 December 2021). "A unified evolutionary origin for the ubiquitous protein transporters SecY and YidC.". BMC Biology 19 (1): 266. doi:10.1186/s12915-021-01171-5. PMID 34911545.
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