InterPro : IPR005791

Name  Protein translocase subunit SecD Short Name  SecD
Type  Family Description  Secretion across the inner membrane in some 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 []. 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 itself comprises 7 proteins, including a chaperone protein (SecB), an ATPase (SecA), an integral membrane complex (SecCY, SecE and SecG), and two additional membrane proteins that promote the release of the mature peptide into the periplasm (SecD and SecF) []. The chaperone protein SecB []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 membraneprotein ATPase SecA for secretion []. Together with SecY and SecG, SecE forms a multimeric channel through which preproteins are translocated, using both proton motive forces and ATP-driven secretion. The latter is mediated by SecA. The structure of the Escherichia coliSecYEG assembly revealed a sandwich of two membranesinteracting through the extensive cytoplasmic domains []. Each membrane is composed of dimers of SecYEG. Themonomeric complex contains 15 transmembrane helices. This entry describes the SecD family of transport proteins, which are parts of the Sec protein translocase complex. Members of this family are highly variable in length immediately after the well-conserved motif LGLGLXGG at the amino-terminal end of this model. Archaeal homologues are not included in the seed. SecD from Mycobacterium tuberculosishas a long Pro-rich insert. SecD interacts with the SecYEG preprotein conducting channel. SecDF uses the proton motive force (PMF) to complete protein translocation after the ATP-dependent function of SecA [].

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

1 Contains

Id Name Short Name Type
IPR022646 Protein-export membrane protein SecD/SecF/SecDF, conserved site SecD/SecF_CS Conserved_site

0 Found In

1 Parent Features

Id Name Short Name Type
IPR022645 Protein-export membrane protein SecD/SecF, bacterial SecD/SecF_bac Family

5 Publications

First Author Title Year Journal Volume Pages
Bieker KL The sec and prl genes of Escherichia coli. 1990 J Bioenerg Biomembr 22 291-310
Driessen AJ SecB, a molecular chaperone with two faces. 2001 Trends Microbiol 9 193-6
Müller JP Effects of pre-protein overexpression on SecB synthesis in Escherichia coli. 1999 FEMS Microbiol Lett 176 219-27
Breyton C Three-dimensional structure of the bacterial protein-translocation complex SecYEG. 2002 Nature 418 662-5
Tsukazaki T Structure and function of a membrane component SecDF that enhances protein export. 2011 Nature 474 235-8

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)