An Artificial Gene for Human Porphobilinogen Synthase Allows Comparison of an Allelic Variation Implicated in Susceptibility to Lead Poisoning

摘要: Porphobilinogen synthase (PBGS) is an ancient enzyme essential to tetrapyrrole biosynthesis (e.g. heme, chlorophyll, and vitamin B(12)). Two common alleles encoding human PBGS, K59 N59, have been correlated with differential susceptibility of humans lead poisoning. However, a model for PBGS based on homologous crystal structures shows the location allelic variation be distant from active site its two Zn(II). Previous microbial expression systems resulted in poor yield. Here, artificial gene was constructed by recursive polymerase chain reaction synthetic oligonucleotides rectify this problem. The made resemble highly expressed Escherichia coli hemB remove rare codons that can confound heterologous protein E. coli. We purified recombinant variants N59 100-mg quantities. Both proteins eight Zn(II)/octamer; Zn(II) binding shown pH-dependent; Pb(II) could displace some there no displacement between simple inhibition studies revealed difference.