Structural highlights
1g6i is a 1 chain structure with sequence from Atcc 18824. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
|
| Ligands: | , , , , , |
| Gene: | MNS1 (ATCC 18824) |
| Activity: | Mannosyl-oligosaccharide 1,2-alpha-mannosidase, with EC number 3.2.1.113 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[MNS1_YEAST] Involved in glycoprotein quality control as it is important for the targeting of misfolded glycoproteins for degradation. It primarily trims a single alpha-1,2-linked mannose residue from Man(9)GlcNAc(2) to produce Man(8)GlcNAc(2), but at high enzyme concentrations it further trims the carbohydrates to Man(5)GlcNAc(2).[1]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
BACKGROUND: ATP binding cassette (ABC) transporters are ubiquitously distributed transmembrane solute pumps that play a causative role in numerous diseases. Previous structures have defined the fold of the ABC and established the flexibility of its alpha-helical subdomain. But the nature of the mechanical changes that occur at each step of the chemical ATPase cycle have not been defined. RESULTS: Crystal structures were determined of the MJ1267 ABC from Methanococcus jannaschii in Mg-ADP-bound and nucleotide-free forms. Comparison of these structures reveals an induced-fit effect at the active site likely to be a consequence of nucleotide binding. In the Mg-ADP-bound structure, the loop following the Walker B moves toward the Walker A (P-loop) coupled to backbone conformational changes in the intervening "H-loop", which contains an invariant histidine. These changes affect the region believed to mediate intercassette interaction in the ABC transporter complex. Comparison of the Mg-ADP-bound structure of MJ1267 to the ATP-bound structure of HisP suggests that an outward rotation of the alpha-helical subdomain is coupled to the loss of a molecular contact between the gamma-phosphate of ATP and an invariant glutamine in a segment connecting this subdomain to the core of the cassette. CONCLUSIONS: The induced-fit effect and rotation of the alpha-helical subdomain may play a role in controlling the nucleotide-dependent change in cassette-cassette interaction affinity believed to represent the power-stroke of ABC transporters. Outward rotation of the alpha-helical subdomain also likely facilitates Mg-ADP release after hydrolysis. The MJ1267 structures therefore define features of the nucleotide-dependent conformational changes that drive transmembrane transport in ABC transporters.
Crystal structures of the MJ1267 ATP binding cassette reveal an induced-fit effect at the ATPase active site of an ABC transporter.,Karpowich N, Martsinkevich O, Millen L, Yuan YR, Dai PL, MacVey K, Thomas PJ, Hunt JF Structure. 2001 Jul 3;9(7):571-86. PMID:11470432[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Herscovics A, Romero PA, Tremblay LO. The specificity of the yeast and human class I ER alpha 1,2-mannosidases involved in ER quality control is not as strict previously reported. Glycobiology. 2002 Apr;12(4):14G-15G. PMID:12090241
- ↑ Karpowich N, Martsinkevich O, Millen L, Yuan YR, Dai PL, MacVey K, Thomas PJ, Hunt JF. Crystal structures of the MJ1267 ATP binding cassette reveal an induced-fit effect at the ATPase active site of an ABC transporter. Structure. 2001 Jul 3;9(7):571-86. PMID:11470432
