My FECH - ing Protein

For those not in the BIO600 class, I apologize. For I am continuing our story of porphyrins, the biochemical molecule that has made life on Earth possible. Viruses may be an exception, but I am not going to go there.

Heme is a porphyrin produced in bacteria, plants and animals that make “heme type” products such as hemoblogin, myoglobin and cytochromes in an eight-step process called the Shemin pathway.  In order to produce Heme and all of its wonderful derivatives, a protein that acts as an enzyme in the last step of heme synthesis process is ferrochelatase or FECH.



Protein
FECH is a protein that consists of 423 amino acids.  FECH is an enzyme that uses iron 2+ to convert: protoporphyrin IX + Fe⁺⁺ ↔ protoheme + 2 H⁺  and requires Fe++, ascorbic acid and cystine to complete the reactions.  Lead inhibits the reaction.  Its protein sequence is:

   1 mrslganmaa alraagvllr dplassswrv cqpwrwksga aaaavtteta qhaqgakpqv
 61 qpqkrkpktg ilmlnmggpe tlgdvhdfll rlfldqdlmt lpiqnklapf iakrrtpkiq
121 eqyrrigggs pikiwtskqg egmvklldel spntaphkyy igfryvhplt eeaieemerd
181 gleraiaftq ypqyscsttg sslnaiyryy nqvgrkptmk wstidrwpth hlliqcfadh
241 ilkeldhfpl ekrsevvilf sahslpmsvv nrgdpypqev satvqkvmer leycnpyrlv
301 wqskvgpmpw lgpqtdesik glcergrkni llvpiaftsd hietlyeldi eysqvlakec
361 gvenirraes lngnplfska ladlvhshiq snelcskqlt lscplcvnpv cretksffts
421 qql

CRYSTAL STRUCTURE OF HUMAN FERROCHELATASE 

Protein Data Base Reference (PDB): 1HRK

UniProtKB: P22830

NCBI RefSec: CAB65962.1

FECH (not shown in the picture) requires Fe++, ascorbic acid and cystine to complete the reactions.  Lead inhibits the reaction.

GENE

The FECH gene in humans is located at 18q21.3 on the long arm of chromosome 18. 

Genomics Home Reference: FECH

Mutations in the FECH gene has an effect on all body systems, from transporting oxygen and carbon dioxide to the production of ATP.  Porphyria is a genetic disease caused by mutations in the FECH gene.  The condition of the disease can be undetectable to severe depending if both copies of the gene was defective.