1hz4
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CRYSTAL STRUCTURE OF TRANSCRIPTION FACTOR MALT DOMAIN III
OverviewOverview
BACKGROUND: MalT from Escherichia coli, the best-studied member of the, MalT family of ATP-dependent transcriptional activators, regulates the, genes for malto-oligosaccharide utilization. The active form of this 4, domain protein is a homooligomer, and its multimerization is induced by, the binding of maltotriose. Domains II and III of MalT were suggested to, mediate the oligomerization process, but its molecular mechanism and the, specific functions of these domains remain to be identified. RESULTS: We, solved the crystal structure of MalT domain III at 1.45 A resolution by, multiple isomorphous replacement phasing. The structure reveals eight, copies of a two-helix bundle motif arranged in a novel, right-handed, superhelix fold with closed walls, followed by a small C-terminal, subdomain. The MalT superhelix contains a potential maltotriose binding, site and forms a large hydrophobic protein-protein interaction interface, that mediates the contact between two MalT domain III molecules., Structure-based analysis of the two-helix bundle motifs revealed a novel, degenerated sequence pattern, and repeats of this pattern could be, identified in other regulator proteins. CONCLUSIONS: MalT domain III, contains a novel superhelix fold. Its protein-protein interaction, interface, however, resembles protein binding sites of other superhelical, proteins, suggesting a model with domain III mediating MalT, oligomerization. Maltotriose seems to modulate the interaction interface, and MalT oligomerization by occupying the ligand binding site inside the, superhelix. Similar structural and mechanistic features in other MalT, protein-family members and unrelated regulator proteins are indicated by, the reappearance of a novel sequence motif derived from the MalT domain, III structure.
About this StructureAbout this Structure
1HZ4 is a Single protein structure of sequence from Escherichia coli with SO4, BEZ and GOL as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of transcription factor MalT domain III: a novel helix repeat fold implicated in regulated oligomerization., Steegborn C, Danot O, Huber R, Clausen T, Structure. 2001 Nov;9(11):1051-60. PMID:11709169
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