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          Institute: MPI für bioanorganische Chemie     Collection: MPI für bioanorganische Chemie     Display Documents



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ID: 682100.0, MPI für bioanorganische Chemie / MPI für bioanorganische Chemie
Kinetics and computational studies of ligand migration in nitrophorin 7 and its Δ 1-3 mutant
Authors:Oliveira, Ana; Allegri, Alessandro; Bidon-Chanal, Axel; Knipp, Markus; Roitberg, Adrian E.; Abbruzzetti, Stefania; Viappiani, Cristiano; Luque, F. Javier
Language:English
Date of Publication (YYYY-MM-DD):2013
Title of Journal:Biochimica et Biophysica Acta-Proteins and Proteomics
Journal Abbrev.:BBA-Proteins Proteomics
Volume:1834
Start Page:1711
End Page:1721
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:Nitrophorins (NPs) are nitric oxide (NO)-carrying heme proteins found in the saliva of the blood-sucking insect Rhodnius prolixus. Though NP7 exhibits a large sequence resemblance with other NPs, two major differential features are the ability to interact with negatively charged cell surfaces and the presence of a specific N-terminus composed of three extra residues (Leu1-Pro2-Gly3). The aim of this study is to examine the influence of the N-terminus on the ligand binding, and the topological features of inner cavities in closed and open states of NP7, which can be associated to the protein structure at low and high pH, respectively. Laser flash photolysis measurements of the CO rebinding kinetics to NP7 and its variant NP7(Delta 1-3), which lacks the three extra residues at the N-terminus, exhibit a similar pattern and support the existence of a common kinetic mechanism for ligand migration and binding. This is supported by the existence of a common topology of inner cavities, which consists of two docking sites in the heme pocket and a secondary site at the back of the protein. The ligand exchange between these cavities is facilitated by an additional site, which can be transiently occupied by the ligand in NP7, although it is absent in NP4. These features provide a basis to explain the enhanced internal gas hosting capacity found experimentally in NP7 and the absence of ligand rebinding from secondary sites in NP4. The current data allow us to speculate that the processes of docking to cell surfaces and NO release may be interconnected in NP7, thereby efficiently releasing NO into a target cell. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins. (c) 2013 Elsevier B.V. All rights reserved.
Free Keywords:Nitrophorin 7; Nitric oxide; Reaction kinetics; Molecular dynamics; Ligand migration
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für bioanorganische Chemie
External Affiliations:Oliveira, A.; Bidon-Chanal, A.; Javier L., F.; Univ Barcelona, Dept Fis Quim, Fac Farm, Santa Coloma De Gramenet, Spain.;
Allegri, A.; Abbruzzetti, S.; Viappiani, C.; Univ Parma, Dipartimento Fis & Sci Terra, I-43124 Parma, Italy.; Roitberg, A.E.; Univ Florida, Quantum Theory Project, Gainesville, FL 32611 USA.
Identifiers:ISI:000323191800005 [ID No:1]
ISSN:1570-9639 [ID No:2]
DOI:10.1016/j.bbapap.2013.04.009
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