|3efi, resolution 1.75Å ()|
Carbonic anhydrase activators: Kinetic and X-ray crystallographic study for the interaction of d- and l-tryptophan with the mammalian isoforms I-XIV
An activation study of mammalian carbonic anhydrase (CA, EC 18.104.22.168) isoforms I-XIV with D- and L-tryptophan has been performed both by means of kinetic and X-ray crystallographic techniques. These compounds show a time dependent activity against isozyme CA II, with activation constants of 1.13 microM for L-Trp and 0.37 microM for D-Trp, respectively, after 24 h of incubation between enzyme and activator. The high resolution X-ray crystal structure of the hCA II-D-Trp adduct revealed the activator to bind in a totally unprecedented way to the enzyme active site as compared to histamine, L-/D-Phe, L-/D-His or L-adrenaline. D-Trp is anchored at the edge of the CA II active site entrance, strongly interacting with amino acid residues Asp130, Phe131 and Gly132 as well as with a loop of a second symmetry related protein molecule from the asymmetric unit, by means of hydrogen bonds and several weak van der Waals interactions involving Glu234, Gly235, Glu236 and Glu238. Thus, a second activator binding site (B) within the CA II cavity has been detected, where only D-Trp was shown so far to bind, in addition to the activator binding site A, in which histamine, L-/D-Phe, and L-/D-His are bound. These findings explain the strong affinity of D-Trp for CA II and may be useful for designing novel classes of CA activators by using this compound as lead molecule.
Carbonic anhydrase activators: kinetic and X-ray crystallographic study for the interaction of D- and L-tryptophan with the mammalian isoforms I-XIV., Temperini C, Innocenti A, Scozzafava A, Supuran CT, Bioorg Med Chem. 2008 Sep 15;16(18):8373-8. Epub 2008 Aug 26. PMID:18774300
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
About this Structure
3efi is a 1 chain structure. Full crystallographic information is available from OCA.
- Temperini C, Innocenti A, Scozzafava A, Supuran CT. Carbonic anhydrase activators: kinetic and X-ray crystallographic study for the interaction of D- and L-tryptophan with the mammalian isoforms I-XIV. Bioorg Med Chem. 2008 Sep 15;16(18):8373-8. Epub 2008 Aug 26. PMID:18774300 doi:10.1016/j.bmc.2008.08.043