title: Different roles of protein dynamics and ligand migration in non-symbiotic hemoglobins AHb1 and AHb2 from Arabidopsis thaliana.
abstract: The ligand rebinding kinetics after photolysis of the CO complexes of Arabidopsis thaliana hemoglobins AHb1 and AHb2 in solution show very different amplitudes in the geminate phase, reflecting different migration pathways of the photodissociated ligand in the system of internal cavities accessible from the heme. The dependence of the geminate phase on CO concentration, temperature, encapsulation in silica gels and presence of glycerol confirms a remarkable difference in the internal structure of the two proteins and a dramatically different role of protein dynamics in regulating the reactivity with CO. This finding strongly supports the idea that they have distinct physiological functions.
authors.affiliation: Dipartimento di Biochimica e Biologia Molecolare, Università degli Studi di Parma, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Bruno
authors.forename: Serena
authors.initials: S
authors.lastname: Faggiano
authors.forename: Francesca
authors.initials: F
authors.lastname: Spyrakis
authors.forename: Andrea
authors.initials: A
authors.lastname: Mozzarelli
authors.forename: Elena
authors.initials: E
authors.lastname: Cacciatori
authors.forename: Paola
authors.initials: P
authors.lastname: Dominici
authors.forename: Elena
authors.initials: E
authors.lastname: Grandi
authors.forename: Stefania
authors.initials: S
authors.lastname: Abbruzzetti
authors.forename: Cristiano
authors.initials: C
authors.lastname: Viappiani
mesh_terms: D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D001665:Binding Sites; D002248:Carbon Monoxide / Q000737:chemistry* / Q000378:metabolism; D005782:Gels / Q000737:chemistry; D005990:Glycerol / Q000737:chemistry; D006418:Heme / Q000737:chemistry / Q000378:metabolism; D006454:Hemoglobins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D007700:Kinetics; D008024:Ligands; D008956:Models, Chemical; D010782:Photolysis; D011485:Protein Binding / Q000528:radiation effects; D012822:Silicon Dioxide / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D013053:Spectrophotometry; D013696:Temperature
chemical_list: C470347:AHB1 protein, Arabidopsis; C109042:AHB2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D005782:Gels; D006454:Hemoglobins; D008024:Ligands; D012996:Solutions; D006418:Heme; D012822:Silicon Dioxide; D002248:Carbon Monoxide; D005990:Glycerol