XH/pi interactions with the pi system of porphyrin ring in porphyrin-containing proteins.
Searching structures of porphyrin-containing proteins from the Protein Data Bank revealed that the pi system of every porphyrin ring is involved in XH/pi interactions, with most of the porphyrins having several interactions. Both five-membered pyrrole rings and six-membered chelate rings are involved in XH/pi interactions; the number of interactions with five-membered rings is larger than the number of interactions with six-membered rings. We found interactions with C-H and N-H groups as hydrogen-atom donors; however, the number of CH/pi interactions is much larger than the number of NH/pi interactions. The amino acids involved in the interactions show a high conservation score. Our results that every porphyrin is involved in XH/pi interactions and that amino acids involved in these interactions are highly conserved demonstrate that XH/pi interactions play an important role in porphyrin-protein stability.
Stojanović
Srdan D
SD
Department of Chemistry, University of Belgrade, Studentski trg 16, 11001 Belgrade, Serbia.
Medaković
Vesna B
VB
Predović
Goran
G
Beljanski
Milos
M
Zarić
Snezana D
SD
D001665:Binding Sites; D018360:Crystallography, X-Ray; D045304:Cytochromes c / Q000737:chemistry; D006860:Hydrogen Bonding; D008954:Models, Biological; D011166:Porphyrins / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*
D011166:Porphyrins; D011506:Proteins; D045304:Cytochromes c