Cloned (Comment) | Organism |
---|---|
recombinant expression of truncated enzyme Sey1p(1-692) in Escherichia coli, recombinant expressioj of Myc-tagged scSey1p in COS-7 cells and immunolocalization study | Candida albicans |
Crystallization (Comment) | Organism |
---|---|
purified recombinant truncated enzyme Sey1p(1-692) , wild-type or selenomethionine-labeled, in complex with GDP, GMP-PNP, or GDP plus AlF4-, X-ray diffraction structure determination and analysis at 2.3-3.0 A resolution | Candida albicans |
Protein Variants | Comment | Organism |
---|---|---|
L233A | site-directed mutagensis, the mutation drastically reduces the dimerization, GTPase activity, and fusion activity of scSey1p | Candida albicans |
additional information | generation of a truncation mutant comprising residues 1-692. The mutant is truncated before the first transmembrane region | Candida albicans |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
endoplasmic reticulum membrane | membrane-anchored by two closely spaced transmembrane segments, exposing both termini to the cytosol | Candida albicans | 5789 | - |
endoplasmic reticulum tubule | - |
Candida albicans | - |
- |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mg2+ | required for activity, especially for the membrane fusion activity | Candida albicans |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
GTP + H2O | Candida albicans | - |
GDP + phosphate | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Candida albicans | Q9C0L9 | - |
- |
Purification (Comment) | Organism |
---|---|
recombinant truncated enzyme Sey1p(1-692) from Escherichia coli | Candida albicans |
Source Tissue | Comment | Organism | Textmining |
---|
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
GTP + H2O | - |
Candida albicans | GDP + phosphate | - |
? | |
additional information | the enzyme mediates homotypic membrane fusion of the endoplasmic reticulum, wild-type scSey1p shows efficient fusion in the presence of GTP and Mg2+. No fusion is seen with GDP or in the absence of Mg2+. Addition of GMP-PNP caused moderate but reproducible fusion. Nucleotide-dependent conformational changes of Sey1p, nucleotide binding structure, detailed overview | Candida albicans | ? | - |
? |
Subunits | Comment | Organism |
---|---|---|
More | enzyme Sey1p forms a side-by-side dimer in complex with GMP-PNP or GDP/AIF4-, but is monomeric with GDP. The dimerization of caSey1p involves a hydrophobic patch on top of the GTPase domain, including a conserved L257 within the guanine cap, and several hydrophilic interactions along the GTPase interface. The stalk domains also pack against each other in the dimer | Candida albicans |
Synonyms | Comment | Organism |
---|---|---|
caSey1p | - |
Candida albicans |
dynamin-like GTPase | - |
Candida albicans |
dynamin-like guanosine triphosphatase | - |
Candida albicans |
Sey1p | - |
Candida albicans |
General Information | Comment | Organism |
---|---|---|
evolution | the enzyme belongs to the dynamin superfamily | Candida albicans |
malfunction | deletion of Sey1p protein in cells results in unbranched endoplasmic reticulum, delayed endoplasmic reticulum fusion, or even endoplasmic reticulum fragmentation. Deletion of Sey1p results in decreased virulence | Candida albicans |
metabolism | enzyme Sey1p can replace the dynamin-like GTPase atlastin (ATL) in mammalian cells | Candida albicans |
additional information | the enzyme has a long stalk-like, helical bundle domain. Structures of the cytosolic domain of Sey1p, overview. Enzyme CytSey1p consists of an N-terminal GTPase domain and a long, stalk-like, helical domain connected by a linker region. In the dimer, the GTPase domains interact with one another in such a way that the nucleotide binding sites face each other. The linker regions of the two Sey1p molecules cross one another, allowing a close association of the tops of the stalk domains. The stalk domain is composed of four three-helix bundles, with the last helix of each bundle extending into the first helix of the next bundle. The catalytic residues is S68 in caSey1p, which adopts a different rotamer conformation after the cleavage of the gamma-phosphate bond, which in turn causes some minor local rearrangements | Candida albicans |
physiological function | the enzyme mediates homotypic membrane fusion of the endoplasmic reticulum, GTP hydrolysis is not essential but accelerates the fusion reaction, the proposed mechanism demonstrates a common scheme for fusion mediated by dynamin-like GTPases and reveals that the stalk domain of Sey1p possesses unique functional features. The linkage of opposing membranes through GTP binding-induced dimerization may be sufficient to promote Sey1p-mediated fusion. GTPase-based endoplasmic reticulum fusogens play critical physiological roles | Candida albicans |