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Hussein HM, Ghafoor DD, Omer KM. Room temperature and surfactant free synthesis of zinc peroxide (ZnO2) nanoparticles in methanol with highly efficient antimicrobials. ARAB J CHEM 2021. [DOI: 10.1016/j.arabjc.2021.103090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Trinh LH, Takzare A, Ghafoor DD, Siddiqi AF, Ravali S, Shalbaf M, Bakhtiar M. Trachyspermum copticum essential oil incorporated niosome for cancer treatment. J Drug Deliv Sci Technol 2019. [DOI: 10.1016/j.jddst.2019.05.046] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Kekilli D, Petersen CA, Pixton DA, Ghafoor DD, Abdullah GH, Dworkowski FSN, Wilson MT, Heyes DJ, Hardman SJO, Murphy LM, Strange RW, Scrutton NS, Andrew CR, Hough MA. Engineering proximal vs. distal heme-NO coordination via dinitrosyl dynamics: implications for NO sensor design. Chem Sci 2017; 8:1986-1994. [PMID: 28451315 PMCID: PMC5390784 DOI: 10.1039/c6sc04190f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 11/08/2016] [Indexed: 01/18/2023] Open
Abstract
Proximal vs. distal heme-NO coordination is a novel strategy for selective gas response in heme-based NO-sensors. In the case of Alcaligenes xylosoxidans cytochrome c' (AXCP), formation of a transient distal 6cNO complex is followed by scission of the trans Fe-His bond and conversion to a proximal 5cNO product via a putative dinitrosyl species. Here we show that replacement of the AXCP distal Leu16 residue with smaller or similar sized residues (Ala, Val or Ile) traps the distal 6cNO complex, whereas Leu or Phe residues lead to a proximal 5cNO product with a transient or non-detectable distal 6cNO precursor. Crystallographic, spectroscopic, and kinetic measurements of 6cNO AXCP complexes show that increased distal steric hindrance leads to distortion of the Fe-N-O angle and flipping of the heme 7-propionate. However, it is the kinetic parameters of the distal NO ligand that determine whether 6cNO or proximal 5cNO end products are formed. Our data support a 'balance of affinities' mechanism in which proximal 5cNO coordination depends on relatively rapid release of the distal NO from the dinitrosyl precursor. This mechanism, which is applicable to other proteins that form transient dinitrosyls, represents a novel strategy for 5cNO formation that does not rely on an inherently weak Fe-His bond. Our data suggest a general means of engineering selective gas response into biologically-derived gas sensors in synthetic biology.
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Affiliation(s)
- Demet Kekilli
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
| | - Christine A Petersen
- Department of Chemistry and Biochemistry , Eastern Oregon University , La Grande , Oregon 97850 , USA .
| | - David A Pixton
- Department of Chemistry and Biochemistry , Eastern Oregon University , La Grande , Oregon 97850 , USA .
| | - Dlzar D Ghafoor
- Faculty of Science and Education Science , University of Sulaimani , Sulaymaniyah , Iraq
| | | | | | - Michael T Wilson
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
| | - Derren J Heyes
- Manchester Institute of Biotechnology , 131 Princess Street , Manchester M1 7DN , UK
| | - Samantha J O Hardman
- Manchester Institute of Biotechnology , 131 Princess Street , Manchester M1 7DN , UK
| | - Loretta M Murphy
- School of Chemistry , Bangor University , Bangor , Gwynedd , Wales LL57 2UW , UK
| | - Richard W Strange
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
- Molecular Biophysics Group , Institute of Integrative Biology , Faculty of Health and Life Sciences , University of Liverpool , Liverpool , L69 7ZB , UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology , 131 Princess Street , Manchester M1 7DN , UK
| | - Colin R Andrew
- Department of Chemistry and Biochemistry , Eastern Oregon University , La Grande , Oregon 97850 , USA .
| | - Michael A Hough
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
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Ghafoor DD, Kekilli D, Abdullah GH, Dworkowski FSN, Hassan HG, Wilson MT, Strange RW, Hough MA. Hydrogen bonding of the dissociated histidine ligand is not required for formation of a proximal NO adduct in cytochrome c'. J Biol Inorg Chem 2015; 20:949-56. [PMID: 26100643 DOI: 10.1007/s00775-015-1278-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/04/2015] [Indexed: 11/28/2022]
Abstract
Cytochromes c', that occur in methanotrophic, denitrifying and photosynthetic bacteria, form unusual proximal penta-coordinate NO complexes via a hexa-coordinate distal NO intermediate. Their NO binding properties are similar to those of the eukaryotic NO sensor, soluble guanylate cyclase, for which they provide a valuable structural model. Previous studies suggested that hydrogen bonding between the displaced proximal histidine (His120) ligand (following its dissociation from heme due to trans effects from the distally bound NO) and a conserved aspartate residue (Asp121) could play a key role in allowing proximal NO binding to occur. We have characterized three variants of Alcaligenes xylosoxidans cytochrome c' (AXCP) where Asp121 has been replaced by Ala, Ile and Gln, respectively. In all variants, hydrogen bonding between residue 121 and His120 is abolished yet 5-coordinate proximal NO species are still formed. Our data therefore demonstrate that the His120-Asp121 bond is not essential for proximal NO binding although it likely provides an energy minimum for the displaced His ligand. All variants have altered proximal pocket structure relative to native AXCP.
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Affiliation(s)
- Dlzar D Ghafoor
- Faculty of Science and Education Science, University of Sulaimani, Sulaymaniyah, Iraq
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