Ligand migration in nonsymbiotic hemoglobin AHb1 from Arabidopsis thaliana.
AHb1 is a hexacoordinated type 1 nonsymbiotic hemoglobin recently discovered in Arabidopsis thaliana. To gain insight into the ligand migration inside the protein, we studied the CO rebinding kinetics of AHb1 encapsulated in silica gels, in the presence of glycerol. The CO rebinding kinetics after nanosecond laser flash photolysis exhibits complex ligand migration patterns, consistent with the existence of discrete docking sites in which ligands can temporarily be stored before rebinding to the heme at different times. This finding may be of relevance to the physiological NO dioxygenase activity of this protein, which requires sequential binding of two substrates, NO and O2, to the heme.
Abbruzzetti
Stefania
S
Dipartimento di Fisica, Università degli Studi di Parma, NEST CNR-INFM, Parma, Italy.
Grandi
Elena
E
Bruno
Stefano
S
Faggiano
Serena
S
Spyrakis
Francesca
F
Mozzarelli
Andrea
A
Cacciatori
Elena
E
Dominici
Paola
P
Viappiani
Cristiano
C
D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002248:Carbon Monoxide / Q000737:chemistry / Q000378:metabolism; D005782:Gels / Q000737:chemistry; D005990:Glycerol / Q000737:chemistry; D006418:Heme / Q000737:chemistry / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism*; D007700:Kinetics; D007834:Lasers; D008024:Ligands; D008958:Models, Molecular; D010782:Photolysis; D011485:Protein Binding; D012822:Silicon Dioxide / Q000737:chemistry
C470347:AHB1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D005782:Gels; D006454:Hemoglobins; D008024:Ligands; D006418:Heme; D012822:Silicon Dioxide; D002248:Carbon Monoxide; D005990:Glycerol