Functional expression of prokaryotic and eukaryotic genes in Escherichia coli for conversion of glucose to p-hydroxystyrene.

The chemical monomer p-hydroxystyrene (pHS) is used for producing a number of important industrial polymers from petroleum-based feedstocks. In an alternative approach, the microbial production of pHS can be envisioned by linking together a number of different metabolic pathways, of which those based on using glucose for carbon and energy are currently the most economical. The biological process conserves petroleum when glucose is converted to the aromatic amino acid L-tyrosine, which is deaminated by a tyrosine/phenylalanine ammonia-lyase (PAL/TAL) enzyme to yield p-hydroxycinnamic acid (pHCA).

Single amino acid mutations alter the distribution of human porphobilinogen synthase quaternary structure isoforms (morpheeins).

Porphobilinogen synthase (PBGS) is an obligate oligomer that can exist in functionally distinct quaternary states of different stoichiometries, which are called morpheeins. The morpheein concept describes an ensemble of quaternary structure isoforms wherein different structures of the monomer dictate different multiplicities of the oligomer (Jaffe, E. K.

Control of tetrapyrrole biosynthesis by alternate quaternary forms of porphobilinogen synthase.

Porphobilinogen synthase (PBGS) catalyzes the first common step in the biosynthesis of tetrapyrroles (such as heme and chlorophyll). Although the predominant oligomeric form of this enzyme, as inferred from many crystal structures, is that of a homo-octamer, a rare human PBGS allele, F12L, reveals the presence of a hexameric form. Rearrangement of an N-terminal arm is responsible for this oligomeric switch, which results in profound changes in kinetic behavior.