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• Olsbu, Inger Kirstine; Zoppellaro, Giorgio; Andersson, Karl Kristoffer; Boucher, Jean-Luc & Hersleth, Hans-Petter (2018). Importance of Val567 on heme environment and substrate recognition of neuronal nitric oxide synthase. FEBS Open Bio. ISSN 2211-5463. 8(9), s. 1553–1566. doi: 10.1002/2211-5463.12503. Fulltekst i vitenarkiv

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• Chaudhari, Sujata; Olsbu, Inger Kirstine; Alqarzaee, Abdulelah; Singh, Ryan; Schulze, Thomas & Zimmerman, Matthew [Vis alle 8 forfattere av denne artikkelen] (2018). Endogenous nitric oxide synthase (NOS) activity reduces staphylococcal lifespan during stationary phase.
• Olsbu, Inger Kirstine; Chaudhari, Sujata; Thomas, Vinai Chittezham & Hersleth, Hans-Petter (2018). Potential reductase partner for Staphylococcus aureus Nitric Oxide Synthase.
• Olsbu, Inger Kirstine; Chaudhari, Sujata; Thomas, Vinai Chittezham & Hersleth, Hans-Petter (2018). Potential reductase partner for Staphylococcus aureus Nitric Oxide Synthase. NBS-nytt. ISSN 0801-3535. s. 40–40.
• Olsbu, Inger Kirstine; Lombard, M; Hersleth, Hans-Petter; Boucher, Jean-Luc & Andersson, K. Kristoffer (2017). Key role of Val-567 on L-Arg analogues and heme ligands to neuronal nitric oxide syntase.
• Olsbu, Inger Kirstine; Murielle, Lombard; Hersleth, Hans-Petter; Jean-Luc, Boucher & Andersson, K. Kristoffer (2016). Key Role of VAL567 on L-Argenine Analogues and HEME Ligands Binding to Neuronal Nitric Oxide Synthase.
• Lofstad, Marie; Hammerstad, Marta; Olsbu, Inger Kirstine; Røhr, Åsmund Kjendseth; Hersleth, Hans-Petter & Andersson, K. Kristoffer (2012). Structural and Functional Studies of Nitric Oxide Synthase and Flavodoxines in Bacillus cereus. Vis sammendrag

  Structural and Functional Studies of Nitric Oxide Synthase and Flavodoxines in Bacillus cereus Marie Lofstad, Marta. Hammerstad, Inger .K. Olsbu, Åsmund .K. Røhr, Hand-Petter.-P. Hersleth and K. Kristoffer.K. Andersson Department of Molecular Biosciences, University of Oslo, PO Box 1041, Blindern, Oslo, Norway Marie Lofstad <marie.lofstad@imbv.uio.no> Nitric Oxide Synthase (NOS) is the enzyme that produces nitric oxide in the body from arginine and oxygen. In mammals three different NOS isoforms with different functions exist: endothelial eNOS, neuronal nNOS and inducible iNOS. The mammalian NOS consists of one oxygenase domain with heme/biopterin (NOSoxy), andone reductase domain (with FMN, FAD and NADPH) and can have a calmodulin domain . The reductase domain latter transports electrons to the heme. NOSoxy. Bacterial NOSs, on the other hand, consist only of an oxygenase domain, and separate proteins deliver the electrons to this domain. The possible functions of bacterial NOSs are not fully understood. We have studied a NOS-like protein from Bacillus cereus, BC5444, which is of interest since it is a close relative to the pathogen Bacillus anthracis. Like other bacterial NOSs, it is lacking a reductase domain; however, several possible reductase partners exist in the genome. Flavodoxines are most likely candidates, due to their capacity to deliver electrons through their co-factor flavin mononucleotide (FMN). Two such flavodoxines, BC1376 and BC3541, have been further investigated. How electrons are transferred by these two flavodoxines from a flavodoxin reductase to NOS, is currently not known. Another intriguing question, concerns the specificity of the flavodoxines – is one specific flavodoxin a more efficient electron donor for NOS than the other, or are they equally good? Different biochemical and structural techniques is are going to be applied in order to try to answer these questions. So far BC5444, BC3541 and BC1376 have been cloned, expressed, purified and crystallized, and the structure of the flavodoxin BC1365 has been solved at high resolution of 1Å using X-ray crystallography. Crystals of the flavodoxin BC3541 and the NOS BC5444 have diffracted to approximately 3Å. Supported by the national Ph.D. school, Biostruct.

• Lofstad, Marie; Hammerstad, Marta; Olsbu, Inger Kirstine; Røhr, Åsmund Kjendseth; Hersleth, Hans-Petter & Andersson, K. Kristoffer (2012). Structural and spectroscopic characterization of the Nitric Oxide Synthase protein system in Bacillus cereus.
• Lofstad, Marie; Hammerstad, Marta; Olsbu, Inger Kirstine; Røhr, Åsmund Kjendseth; Hersleth, Hans-Petter & Andersson, K. Kristoffer (2012). Structural studies of Nitric Oxide Synthase and Flavodoxines in Bacillus cereus.
• Lofstad, Marie; Hammerstad, Marta; Olsbu, Inger Kirstine; Røhr, Åsmund Kjendseth; Hersleth, Hans-Petter & Andersson, K. Kristoffer (2011). Structural studies of Nitric Oxide Synthase and Flavodoxines in Bacillus cereus. Vis sammendrag

  Structural studies of Nitric Oxide Synthase and Flavodoxines in Bacillus cereus Author list: Marie Lofstad, Marta Hammerstad, Inger K. Olsbu, Åsmund K. Røhr, Hans-Petter Hersleth, K. Kristoffer Andersson Nitric Oxide Synthase (NOS) produces NO in the body from arginine and oxygen. In mammals three different NOS isoforms exist: endothelial eNOS, neuronal nNOS and inducible iNOS. The mammalian NOS consists of one oxygenase domain with heme (NOSoxy) and one reductase domain (with FMN, FAD and NADPH) which transports electrons to NOSoxy. Bacterial NOS, on the other hand, consists only of an oxygenase domain, and have separate proteins that deliver the electrons to this domain. The redox partner of NOS in Bacillus cereus is not known, but the three flavodoxins in Bacillus cereus are the most probable candiates. In this project we will try to structurally characterize the Bacillus cereus NOS (bcNOS) system: try to determine the natural electron donors of bcNOS, find out how specific these donors are, and understand the electron transfer between bcNOS and its electron donors. The results from these studies are going to be compared with the knowledge about the mammalian NOS reaction. I have so far in my master project cloned bcNOS and two flavodoxins. The main purpose of the project is to solve the structure of these proteins, as well as performimg activity assays and spectroscopic studies. For the flavodoxin BC1376 some nice crystals that diffracted to better than 1.0 Å, have already been obtained, and I am currently working on solving the structure.

• Olsbu, Inger Kirstine; Lombard, M; Hersleth, Hans-Petter; Andersson, K. Kristoffer & Boucher, Jean-Luc (2011). Key role of Val567 on L-Arginine analogues and heme ligands binding to nNOS. NBS-nytt. ISSN 0801-3535. s. 94–94.
• Olsbu, Inger Kirstine; Lombard, M; Hersleth, Hans-Petter; Andersson, K. Kristoffer & Boucher, Jean-Luc (2011). Key role of Val567 on L-Arginine analogues and heme ligands binding to nNOS.
• Olsbu, Inger Kirstine; Lombard, M; Hersleth, Hans-Petter; Andersson, K. Kristoffer & Boucher, Jean-Luc (2010). Key role of Val567 on L-Arginine,analogues and heme ligands binding to nNOS. Vis sammendrag

  Key role of Val567 on L-Arginine analogues and heme ligands binding to nNOS. I.K. Olsbua, M. Lombardb, H.-P. Hersletha, K.K. Anderssona and J.-L. Boucherb aDepartment of Molecular Biosciences, Univeristy of Oslo, P.O.Box 1041 Blindern, N-0316 Oslo, Norway, bUMR 8601 CNRS, University Paris Descartes, 45 rue des Saints Peres, 75270 Paris, France Nitric Oxide (NO) is a key inter and intracellular messenger molecule involved in maintenance of vascular tone, neuronal signalling and immune response in mammals. The biosynthesis of NO involves a two step oxidation of L-Arginine (L-Arg) to citrulline and NO by heme thiolate proteins called Nitric Oxide Synthases (NOSs). The crystal structures have revealed the presence of a highly conserved hydrophobic pocket among NOSs isoforms containing Val, Pro and Phe residues [1]. In bacterial NOSs, this Val residue is changed for an Ile residue [2]. This Val / Ile switch significantly reduces the rate NO release due to increased shielding of the heme pocket [3] and could alter the reactivity of the heme. Based on these findings, the importance of this Val567 (rat nNOSoxy) residue on substrate recognition, heme ligands binding and NO formation was investigated. Several mutants of nNOSoxy were constructed by point mutations, and the proteins were characterised in respect to their binding capability of natural substrates of NOS, as well as common heme ligands such as alkylisocyanides and CO. References [1] H. Li, H. Shimizu, M. Flinspach, J. Jamal, W. Yang, M. Xian, T. Cai, E.Z. Wen, O. Jia, P.G. Wang, T.L Poulos, Biochemistry 2002, 41, 13868-13875. [2] K. Pant, A.M. Bilwes, S. Adak, D.J. Stuehr, B.R. Crane, Biochemistry 2002, 41, 11071-11079. [3] Z.Q. Wang, C.C. Wei, M. Sharma, K. Pant, B.R. Crane, D.J. Stuehr, J. Biol. Chem. 2004, 279, 19018-19025.

• Olsbu, Inger Kirstine; Lombard, M; Hersleth, Hans-Petter; Andersson, K. Kristoffer & Boucher, Jean-Luc (2010). Key role of Val567 on L-Arginine analogues and heme ligands binding to nNOS.
• Olsbu, Inger Kirstine; Lombard, M; Hersleth, Hans-Petter; Andersson, K. Kristoffer & Boucher, Jean-Luc (2010). Key role of Val567 on L-Arginine analogues and heme ligands binding to nNOS. Vis sammendrag

  Key role of Val567 on L-Arginine analogues and heme ligands binding to nNOS. I.K. Olsbua, M. Lombardb, H.-P. Hersletha, K.K. Anderssona and J.-L. Boucherb aDepartment of Molecular Biosciences, Univeristy of Oslo, P.O.Box 1041 Blindern, N-0316 Oslo, Norway, bUMR 8601 CNRS, University Paris Descartes, 45 rue des Saints Peres, 75270 Paris, France Nitric Oxide (NO) is a key inter and intracellular messenger molecule involved in maintenance of vascular tone, neuronal signalling and immune response in mammals. The biosynthesis of NO involves a two step oxidation of L-Arginine (L-Arg) to citrulline and NO by heme thiolate proteins called Nitric Oxide Synthases (NOSs). The crystal structures have revealed the presence of a highly conserved hydrophobic pocket among NOSs isoforms containing Val, Pro and Phe residues [1]. In bacterial NOSs, this Val residue is changed for an Ile residue [2]. This Val / Ile switch significantly reduces the rate NO release due to increased shielding of the heme pocket [3] and could alter the reactivity of the heme. Based on these findings, the importance of this Val567 (rat nNOSoxy) residue on substrate recognition, heme ligands binding and NO formation was investigated. Several mutants of nNOSoxy were constructed by point mutations, and the proteins were characterised in respect to their binding capability of natural substrates of NOS, as well as common heme ligands such as alkylisocyanides and CO. References [1] H. Li, H. Shimizu, M. Flinspach, J. Jamal, W. Yang, M. Xian, T. Cai, E.Z. Wen, O. Jia, P.G. Wang, T.L Poulos, Biochemistry 2002, 41, 13868-13875. [2] K. Pant, A.M. Bilwes, S. Adak, D.J. Stuehr, B.R. Crane, Biochemistry 2002, 41, 11071-11079. [3] Z.Q. Wang, C.C. Wei, M. Sharma, K. Pant, B.R. Crane, D.J. Stuehr, J. Biol. Chem. 2004, 279, 19018-19025.

• Olsbu, Inger Kirstine; Lombard, M; Hersleth, Hans-Petter; Andersson, K. Kristoffer & Boucher, Jean-Luc (2008). Key role of Val567 on L-Arginine analogues and heme ligands binding to nNOS.
• Olsbu, Inger Kirstine; Hersleth, Hans-Petter & Sørlie, Morten (2018). Substrate recognition and redox partner identification in nitric oxide synthases. Reprosentralen, University of Oslo. ISSN 1501-7710.

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