Literature summary for 3.5.2.6 extracted from

Ke, W.; Laurent, A.H.; Armstrong, M.D.; Chen, Y.; Smith, W.E.; Liang, J.; Wright, C.M.; Ostermeier, M.; van den Akker, F.
Structure of an engineered beta-lactamase maltose binding protein fusion protein: insights into heterotropic allosteric regulation (2012), PLoS ONE, 7, e39168.

Protein Variants

Protein Variants	Comment	Organism
additional information	insertion of a circularly permuted TEM-1 beta-lactamase gene into the maltose binding protein leads to protein RG13, which exhibits allostery. RG13 is positively regulated by maltose yet is inhibited by Zn2+ at low millimolar concentration. The structure reveals that the maltose binding protein and TEM-1 domains are in close proximity connected via two linkers and a zinc ion bridging both domains. By bridging both TEM-1 and MBP, Zn2+ acts to twist tie the linkers thereby partially dislodging a linker between the two domains from its original catalytically productive position in TEM-1. This linker 1 contains residues normally part of the TEM-1 active site including the critical beta3 and beta4 strands important for activity. Mutagenesis of residues comprising the crystallographically observed Zn2+ site only slightly affect Zn2+ inhibition 2- to 4fold. Structural analysis indicates that the linker attachment sites on maltose binding protein are at a site that, upon maltose binding, harbors both the largest local Calpha distance changes and displays surface curvature changes. Maltose activation and zinc inhibition of RG13 are hypothesized to have opposite effects on productive relaxation of the TEM-1 beta3 linker region via steric and/or linker juxtapositioning mechanisms	Escherichia coli

Organism	UniProt	Comment	Textmining
Escherichia coli	P62593	-	-