Crystallization and preliminary X-ray diffraction studies of 5-chlorolevulinate-modified bovine porphobilinogen synthase and the Pb(II)-complexed enzyme

H L Carrell; J P Glusker; L Shimoni; L J Keefe; C Afshar; M Volin; E K Jaffe

doi:10.1107/S0907444995013163

Crystallization and preliminary X-ray diffraction studies of 5-chlorolevulinate-modified bovine porphobilinogen synthase and the Pb(II)-complexed enzyme

Acta Crystallogr D Biol Crystallogr. 1996 Mar 1;52(Pt 2):419-21. doi: 10.1107/S0907444995013163.

Authors

H L Carrell¹, J P Glusker, L Shimoni, L J Keefe, C Afshar, M Volin, E K Jaffe

Affiliation

¹ Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.

PMID: 15299718
DOI: 10.1107/S0907444995013163

Abstract

Bovine porphobilinogen synthase (PBGS) is an homo-octameric enzyme with four active sites. Each active site binds two Zn(II) atoms whose ligands differ and two molecules of 5-aminolevulinate whose chemical fates differ. The asymmetric binding of two Zn(II) atoms and two identical substrate molecules by a homodimeric active site is apparently unique. Modification by 5-chiorolevulinate can be used to differentiate the two substrate-binding sites; diffraction-quality crystals of 5-chlorolevulinate-modified PBGS have been obtained. Pb(II) can be used to differentiate the two different Zn(II)-binding sites; diffraction-quality crystals of the Pb(II) complex of PBGS have been obtained. Preliminary diffraction data reveal an I422 space group, in agreement with a general model for the quaternary structure of PBGS.