1
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Chen L, Yuan H, Wang XJ, Li L, Tan X, Lin YW. Engineering Human Neuroglobin into a Cytochrome c-Like Protein with a Single Thioether Bond in Non-native State. Chembiochem 2022; 23:e202200531. [PMID: 36217897 DOI: 10.1002/cbic.202200531] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/10/2022] [Indexed: 01/25/2023]
Abstract
A double mutant of human H64M/V71C neuroglobin (Ngb) was engineered, which formed a single thioether bond as that in atypical cytochrome c, whereas the heme distal Met64 was oxidized to both sulfoxide (SO-Met) and sulfone (SO2 -Met). By contrast, no Cys-heme cross-link was formed in V71C Ngb with His64/His96 coordination, as shown by the X-ray crystal structure, which indicates that an open distal site facilitates the activation of heme iron for structural modifications.
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Affiliation(s)
- Lei Chen
- School of Chemistry and Chemical Engineering, University of South China, Hengyang, 421001, China
| | - Hong Yuan
- Department of Chemistry & Institute of Biomedical Science, Fudan University, Shanghai, 200433, China
| | - Xiao-Juan Wang
- School of Chemistry and Chemical Engineering, University of South China, Hengyang, 421001, China
| | - Lianzhi Li
- School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, 252059, China
| | - Xiangshi Tan
- Department of Chemistry & Institute of Biomedical Science, Fudan University, Shanghai, 200433, China
| | - Ying-Wu Lin
- School of Chemistry and Chemical Engineering, University of South China, Hengyang, 421001, China.,Key Lab of Protein Structure and Function of Universities in Hunan Province, University of South China, Hengyang, 421001, China
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2
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Control of distal lysine coordination in a monomeric hemoglobin: A role for heme peripheral interactions. J Inorg Biochem 2021; 219:111437. [PMID: 33892380 DOI: 10.1016/j.jinorgbio.2021.111437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 03/20/2021] [Accepted: 03/20/2021] [Indexed: 12/25/2022]
Abstract
THB1 is a monomeric truncated hemoglobin (TrHb) found in the cytoplasm of the green alga Chlamydomonas reinhardtii. The canonical heme coordination scheme in hemoglobins is a proximal histidine ligand and an open distal site. In THB1, the latter site is occupied by Lys53, which is likely to facilitate Fe(II)/Fe(III) redox cycling but hinders dioxygen binding, two features inherent to the NO dioxygenase activity of the protein. TrHb surveys show that a lysine at a position aligning with Lys53 is an insufficient determinant of coordination, and in this study, we sought to identify factors controlling lysine affinity for the heme iron. We solved the "Lys-off" X-ray structure of THB1, represented by the cyanide adduct of the Fe(III) protein, and hypothesized that interactions that differ between the known "Lys-on" structure and the Lys-off structure participate in the control of Lys53 affinity for the heme iron. We applied an experimental approach (site-directed mutagenesis, heme modification, pH titrations in the Fe(III) and Fe(II) states) and a computational approach (MD simulations in the Fe(II) state) to assess the role of heme propionate-protein interactions, distal helix capping, and the composition of the distal pocket. All THB1 modifications resulted in a weakening of lysine affinity and affected the coupling between Lys53 proton binding and heme redox potential. The results supported the importance of specific heme peripheral interactions for the pH stability of iron coordination and the ability of the protein to undergo redox reactions.
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3
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Liu HX, Li L, Yang XZ, Wei CW, Cheng HM, Gao SQ, Wen GB, Lin YW. Enhancement of protein stability by an additional disulfide bond designed in human neuroglobin. RSC Adv 2019; 9:4172-4179. [PMID: 35520156 PMCID: PMC9062612 DOI: 10.1039/c8ra10390a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 01/28/2019] [Indexed: 12/21/2022] Open
Abstract
Human neuroglobin (Ngb) forms an intramolecular disulfide bond between Cys46 and Cys55, with a third Cys120 near the protein surface, which is a promising protein model for heme protein design. In order to protect the free Cys120 and to enhance the protein stability, we herein developed a strategy by designing an additional disulfide bond between Cys120 and Cys15 via A15C mutation. The design was supported by molecular modeling, and the formation of Cys15–Cys120 disulfide bond was confirmed experimentally by ESI-MS analysis. Molecular modeling, UV-Vis and CD spectroscopy showed that the additional disulfide bond caused minimal structural alterations of Ngb. Meanwhile, the disulfide bond of Cys15–Cys120 was found to enhance both Gdn·HCl-induced unfolding stability (increased by ∼0.64 M) and pH-induced unfolding stability (decreased by ∼0.69 pH unit), as compared to those of WT Ngb with a single native disulfide bond of Cys46–Cys55. Moreover, the half denaturation temperature (Tm) of A15C Ngb was determined to be higher than 100 °C. In addition, the disulfide bond of Cys15–Cys120 has slight effects on protein function, such as an increase in the rate of O2 release by ∼1.4-fold. This study not only suggests a crucial role of the artificial disulfide in protein stabilization, but also lays the groundwork for further investigation of the structure and function of Ngb, as well as for the design of other functional heme proteins, based on the scaffold of A15C Ngb with an enhanced stability. A disulfide bond of Cys120 and Cys15 was rationally designed in human neuroglobin (Ngb) by A15C mutation, which caused minimal structural alterations, whereas enhanced both chemical and pH stability, with a thermal stability higher than 100 °C.![]()
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Affiliation(s)
- Hai-Xiao Liu
- School of Chemistry and Chemical Engineering
- University of South China
- Hengyang 421001
- China
| | - Lianzhi Li
- School of Chemistry and Chemical Engineering
- Liaocheng University
- Liaocheng 252059
- China
| | - Xin-Zhi Yang
- Laboratory of Protein Structure and Function
- University of South China
- Hengyang 421001
- China
| | - Chuan-Wan Wei
- School of Chemistry and Chemical Engineering
- University of South China
- Hengyang 421001
- China
| | - Hui-Min Cheng
- School of Chemistry and Chemical Engineering
- University of South China
- Hengyang 421001
- China
| | - Shu-Qin Gao
- Laboratory of Protein Structure and Function
- University of South China
- Hengyang 421001
- China
| | - Ge-Bo Wen
- Laboratory of Protein Structure and Function
- University of South China
- Hengyang 421001
- China
| | - Ying-Wu Lin
- School of Chemistry and Chemical Engineering
- University of South China
- Hengyang 421001
- China
- Laboratory of Protein Structure and Function
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4
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Bacon BA, Liu Y, Kincaid JR, Boon EM. Spectral Characterization of a Novel NO Sensing Protein in Bacteria: NosP. Biochemistry 2018; 57:6187-6200. [PMID: 30272959 DOI: 10.1021/acs.biochem.8b00451] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A novel family of bacterial hemoproteins named NosP has been discovered recently; its members are proposed to function as nitric oxide (NO) responsive proteins involved in bacterial group behaviors such as quorum sensing and biofilm growth and dispersal. Currently, little is known about molecular activation mechanisms in NosP. Here, functional studies were performed utilizing the distinct spectroscopic characteristics associated with the NosP heme cofactor. NosPs from Pseudomonas aeruginosa ( Pa), Vibrio cholerae ( Vc), and Legionella pneumophila ( Lpg) were studied in their ferrous unligated forms as well as their ferrous CO, ferrous NO, and ferric CN adducts. The resonance Raman (rR) data collected on the ferric forms strongly support the existence of a distorted heme cofactor, which is a common feature in NO sensors. The ferrous spectra exhibit a 213 cm-1 feature, which is assigned to the Fe-Nhis stretching mode. The Fe-C and C-O frequencies in the spectra of ferrous CO NosP complexes are inversely correlated with relatively similar frequencies, consistent with a proximal histidine ligand and a relatively hydrophobic environment. The rR spectra obtained for isotopically labeled ferrous NO adducts provide evidence of formation of a 5-coordinate NO complex, resulting from proximal Fe-Nhis cleavage, which is believed to play a role in biological heme-NO signal transduction. Additionally, we found that of the three NosPs studied, Lpg NosP contains the most electropositive ligand binding pocket, while Pa NosP has the most electronegative ligand binding pocket. This pattern is also observed in the measured heme reduction potentials for these three proteins, which may indicate distinct functions for each.
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Affiliation(s)
- Bezalel A Bacon
- Graduate program in Biochemistry and Structural Biology , Stony Brook University , Stony Brook , New York 11790-3400 , United States
| | - Yilin Liu
- Department of Chemistry , Marquette University , Milwaukee , Wisconsin 53233 , United States
| | - James R Kincaid
- Department of Chemistry , Marquette University , Milwaukee , Wisconsin 53233 , United States
| | - Elizabeth M Boon
- Graduate program in Biochemistry and Structural Biology , Stony Brook University , Stony Brook , New York 11790-3400 , United States.,Department of Chemistry and Institute of Chemical Biology and Drug Discovery , Stony Brook University , Stony Brook , New York 11794-3400 , United States
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5
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Cheng HM, Yuan H, Wang XJ, Xu JK, Gao SQ, Wen GB, Tan X, Lin YW. Formation of Cys-heme cross-link in K42C myoglobin under reductive conditions with molecular oxygen. J Inorg Biochem 2018; 182:141-149. [PMID: 29477977 DOI: 10.1016/j.jinorgbio.2018.02.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 02/04/2018] [Accepted: 02/13/2018] [Indexed: 12/13/2022]
Abstract
The structure and function of heme proteins are regulated by diverse post-translational modifications including heme-protein cross-links, with the underlying mechanisms not well understood. In this study, we introduced a Cys (K42C) close to the heme 4-vinyl group in sperm whale myoglobin (Mb) and solved its X-ray crystal structure. Interestingly, we found that K42C Mb can partially form a Cys-heme cross-link (termed K42C Mb-X) under dithiothreitol-induced reductive conditions in presence of O2, as suggested by guanidine hydrochloride-induced unfolding and heme extraction studies. Mass spectrometry (MS) studies, together with trypsin digestion studies, further indicated that a thioether bond is formed between Cys42 and the heme 4-vinyl group with an additional mass of 16 Da, likely due to hydroxylation of the α‑carbon. We then proposed a plausible mechanism for the formation of the novel Cys-heme cross-link based on MS, kinetic UV-vis and electron paramagnetic resonance (EPR) studies. Moreover, the Cys-heme cross-link was shown to fine-tune the protein reactivity toward activation of H2O2. This study provides valuable insights into the post-translational modification of heme proteins, and also suggests that the Cys-heme cross-link can be induced to form in vitro, making it useful for design of new heme proteins with a non-dissociable heme and improved functions.
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Affiliation(s)
- Hui-Min Cheng
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China
| | - Hong Yuan
- Department of Chemistry, Shanghai Key Lab of Chemical Biology for Protein Research & Institute of Biomedical Science, Fudan University, Shanghai 200433, China
| | - Xiao-Juan Wang
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China
| | - Jia-Kun Xu
- Yellow Sea Fisheries Research Institute, Qingdao 266071, China
| | - Shu-Qin Gao
- Lab of Protein Structure and Function, University of South China, Hengyang 421001, China
| | - Ge-Bo Wen
- Lab of Protein Structure and Function, University of South China, Hengyang 421001, China
| | - Xiangshi Tan
- Department of Chemistry, Shanghai Key Lab of Chemical Biology for Protein Research & Institute of Biomedical Science, Fudan University, Shanghai 200433, China
| | - Ying-Wu Lin
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China; Lab of Protein Structure and Function, University of South China, Hengyang 421001, China.
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6
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Nye DB, Preimesberger MR, Majumdar A, Lecomte JTJ. Histidine-Lysine Axial Ligand Switching in a Hemoglobin: A Role for Heme Propionates. Biochemistry 2018; 57:631-644. [PMID: 29271191 DOI: 10.1021/acs.biochem.7b01155] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The hemoglobin of Synechococcus sp. PCC 7002, GlbN, is a monomeric group I truncated protein (TrHb1) that coordinates the heme iron with two histidine ligands at neutral pH. One of these is the distal histidine (His46), a residue that can be displaced by dioxygen and other small molecules. Here, we show with mutagenesis, electronic absorption spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy that at high pH and exclusively in the ferrous state, Lys42 competes with His46 for the iron coordination site. When b heme is originally present, the population of the lysine-bound species remains too small for detailed characterization; however, the population can be increased significantly by using dimethyl-esterified heme. Electronic absorption and NMR spectroscopies showed that the reversible ligand switching process occurs with an apparent pKa of 9.3 and a Lys-ligated population of ∼60% at the basic pH limit in the modified holoprotein. The switching rate, which is slow on the chemical shift time scale, was estimated to be 20-30 s-1 by NMR exchange spectroscopy. Lys42-His46 competition and attendant conformational rearrangement appeared to be related to weakened bis-histidine ligation and enhanced backbone dynamics in the ferrous protein. The pH- and redox-dependent ligand exchange process observed in GlbN illustrates the structural plasticity allowed by the TrHb1 fold and demonstrates the importance of electrostatic interactions at the heme periphery for achieving axial ligand selection. An analogy is drawn to the alkaline transition of cytochrome c, in which Lys-Met competition is detected at alkaline pH, but, in contrast to GlbN, in the ferric state only.
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Affiliation(s)
- Dillon B Nye
- T. C. Jenkins Department of Biophysics, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Matthew R Preimesberger
- T. C. Jenkins Department of Biophysics, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Ananya Majumdar
- Biomolecular NMR Center, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Juliette T J Lecomte
- T. C. Jenkins Department of Biophysics, Johns Hopkins University , Baltimore, Maryland 21218, United States
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7
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Preimesberger MR, Johnson EA, Nye DB, Lecomte JTJ. Covalent attachment of the heme to Synechococcus hemoglobin alters its reactivity toward nitric oxide. J Inorg Biochem 2017; 177:171-182. [PMID: 28968520 DOI: 10.1016/j.jinorgbio.2017.09.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 01/19/2023]
Abstract
The cyanobacterium Synechococcus sp. PCC 7002 produces a monomeric hemoglobin (GlbN) implicated in the detoxification of reactive nitrogen and oxygen species. GlbN contains a b heme, which can be modified under certain reducing conditions. The modified protein (GlbN-A) has one heme-histidine C-N linkage similar to the C-S linkage of cytochrome c. No clear functional role has been assigned to this modification. Here, optical absorbance and NMR spectroscopies were used to compare the reactivity of GlbN and GlbN-A toward nitric oxide (NO). Both forms of the protein are capable of NO dioxygenase activity and both undergo heme bleaching after multiple NO challenges. GlbN and GlbN-A bind NO in the ferric state and form diamagnetic complexes (FeIII-NO) that resist reductive nitrosylation to the paramagnetic FeII-NO forms. Dithionite reduction of FeIII-NO GlbN and GlbN-A, however, resulted in distinct outcomes. Whereas GlbN-A rapidly formed the expected FeII-NO complex, NO binding to FeII GlbN caused immediate heme loss and, remarkably, was followed by slow heme rebinding and HNO (nitrosyl hydride) production. Additionally, combining FeIII GlbN, 15N-labeled nitrite, and excess dithionite resulted in the formation of FeII-H15NO GlbN. Dithionite-mediated HNO production was also observed for the related GlbN from Synechocystis sp. PCC 6803. Although ferrous GlbN-A appeared capable of trapping preformed HNO, the histidine-heme post-translational modification extinguished the NO reduction chemistry associated with GlbN. Overall, the results suggest a role for the covalent modification in FeII GlbNs: protection from NO-mediated heme loss and prevention of HNO formation.
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Affiliation(s)
| | - Eric A Johnson
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Dillon B Nye
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Juliette T J Lecomte
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA.
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8
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Preimesberger MR, Majumdar A, Lecomte JTJ. Dynamics of Lysine as a Heme Axial Ligand: NMR Analysis of the Chlamydomonas reinhardtii Hemoglobin THB1. Biochemistry 2017; 56:551-569. [DOI: 10.1021/acs.biochem.6b00926] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Matthew R. Preimesberger
- T.
C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Ananya Majumdar
- Biomolecular
NMR Center, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Juliette T. J. Lecomte
- T.
C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
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9
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Yan DJ, Yuan H, Li W, Xiang Y, He B, Nie CM, Wen GB, Lin YW, Tan X. How a novel tyrosine-heme cross-link fine-tunes the structure and functions of heme proteins: a direct comparitive study of L29H/F43Y myoglobin. Dalton Trans 2016; 44:18815-22. [PMID: 26458300 DOI: 10.1039/c5dt03040d] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A heme-protein cross-link is a key post-translational modification (PTM) of heme proteins. Meanwhile, the structural and functional consequences of heme-protein cross-links are not fully understood, due to limited studies on a direct comparison of the same protein with and without the cross-link. A Tyr-heme cross-link with a C-O bond is a newly discovered PTM of heme proteins, and is spontaneously formed in F43Y myoglobin (Mb) between the Tyr hydroxyl group and the heme 4-vinyl group in vivo. In this study, we found that with an additional distal His29 introduced in the heme pocket, the double mutant L29H/F43Y Mb can form two distinct forms under different protein purification conditions, with and without a novel Tyr-heme cross-link. By solving the X-ray structures of both forms of L29H/F43Y Mb and performing spectroscopic studies, we made a direct structural and functional comparison in the same protein scaffold. It revealed that the Tyr-heme cross-link regulates the heme distal hydrogen-bonding network, and fine-tunes not only the spectroscopic and ligand binding properties, but also the protein reactivity. Moreover, the formation of the Tyr-heme cross-link in the double mutant L29H/F43Y Mb was investigated in vitro. This study addressed the key issue of how Tyr-heme cross-link fine-tunes the structure and functions of the heme protein, and provided a plausible mechanism for the formation of the newly discovered Tyr-heme cross-link.
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Affiliation(s)
- Dao-Jing Yan
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China.
| | - Hong Yuan
- Department of Chemistry/Shanghai Key Lab of Chemical Biology for Protein Research & Institute of Biomedical Science, Fudan University, Shanghai 200433, China.
| | - Wei Li
- Department of Chemistry/Shanghai Key Lab of Chemical Biology for Protein Research & Institute of Biomedical Science, Fudan University, Shanghai 200433, China.
| | - Yu Xiang
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Bo He
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China.
| | - Chang-Ming Nie
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China.
| | - Ge-Bo Wen
- Laboratory of Protein Structure and Function, University of South China, Hengyang 421001, China
| | - Ying-Wu Lin
- School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China. and Laboratory of Protein Structure and Function, University of South China, Hengyang 421001, China
| | - Xiangshi Tan
- Department of Chemistry/Shanghai Key Lab of Chemical Biology for Protein Research & Institute of Biomedical Science, Fudan University, Shanghai 200433, China.
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10
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Preimesberger M, Majumdar A, Rice SL, Que L, Lecomte JTJ. Helix-Capping Histidines: Diversity of N-H···N Hydrogen Bond Strength Revealed by (2h)JNN Scalar Couplings. Biochemistry 2015; 54:6896-908. [PMID: 26523621 PMCID: PMC4660981 DOI: 10.1021/acs.biochem.5b01002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 10/31/2015] [Indexed: 11/29/2022]
Abstract
In addition to its well-known roles as an electrophile and general acid, the side chain of histidine often serves as a hydrogen bond (H-bond) acceptor. These H-bonds provide a convenient pH-dependent switch for local structure and functional motifs. In hundreds of instances, a histidine caps the N-terminus of α- and 310-helices by forming a backbone NH···Nδ1 H-bond. To characterize the resilience and dynamics of the histidine cap, we measured the trans H-bond scalar coupling constant, (2h)JNN, in several forms of Group 1 truncated hemoglobins and cytochrome b5. The set of 19 measured (2h)JNN values were between 4.0 and 5.4 Hz, generally smaller than in nucleic acids (~6-10 Hz) and indicative of longer, weaker bonds in the studied proteins. A positive linear correlation between (2h)JNN and the difference in imidazole ring (15)N chemical shift (Δ(15)N = |δ(15)Nδ1 - δ(15)Nε2|) was found to be consistent with variable H-bond length and variable cap population related to the ionization of histidine in the capping and noncapping states. The relative ease of (2h)JNN detection suggests that this parameter can become part of the standard arsenal for describing histidines in helix caps and other key structural and catalytic elements involving NH···N H-bonds. The combined nucleic acid and protein data extend the utility of (2h)JNN as a sensitive marker of local structural, dynamic, and thermodynamic properties in biomolecules.
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Affiliation(s)
- Matthew
R. Preimesberger
- T.
C. Jenkins Department of Biophysics, Johns
Hopkins University, Baltimore, Maryland 21218, United States
| | - Ananya Majumdar
- Biomolecular
NMR Center, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Selena L. Rice
- T.
C. Jenkins Department of Biophysics, Johns
Hopkins University, Baltimore, Maryland 21218, United States
| | - Lauren Que
- T.
C. Jenkins Department of Biophysics, Johns
Hopkins University, Baltimore, Maryland 21218, United States
| | - Juliette T. J. Lecomte
- T.
C. Jenkins Department of Biophysics, Johns
Hopkins University, Baltimore, Maryland 21218, United States
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11
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Lin YW. The broad diversity of heme-protein cross-links: An overview. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:844-59. [DOI: 10.1016/j.bbapap.2015.04.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 03/26/2015] [Accepted: 04/17/2015] [Indexed: 12/30/2022]
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12
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Rice SL, Boucher LE, Schlessman JL, Preimesberger MR, Bosch J, Lecomte JTJ. Structure of Chlamydomonas reinhardtii THB1, a group 1 truncated hemoglobin with a rare histidine-lysine heme ligation. Acta Crystallogr F Struct Biol Commun 2015; 71:718-25. [PMID: 26057801 PMCID: PMC4461336 DOI: 10.1107/s2053230x15006949] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 04/07/2015] [Indexed: 04/05/2023] Open
Abstract
THB1 is one of several group 1 truncated hemoglobins (TrHb1s) encoded in the genome of the unicellular green alga Chlamydomonas reinhardtii. THB1 expression is under the control of NIT2, the master regulator of nitrate assimilation, which also controls the expression of the only nitrate reductase in the cell, NIT1. In vitro and physiological evidence suggests that THB1 converts the nitric oxide generated by NIT1 into nitrate. To aid in the elucidation of the function and mechanism of THB1, the structure of the protein was solved in the ferric state. THB1 resembles other TrHb1s, but also exhibits distinct features associated with the coordination of the heme iron by a histidine (proximal) and a lysine (distal). The new structure illustrates the versatility of the TrHb1 fold, suggests factors that stabilize the axial ligation of a lysine, and highlights the difficulty of predicting the identity of the distal ligand, if any, in this group of proteins.
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Affiliation(s)
- Selena L. Rice
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
| | - Lauren E. Boucher
- Department of Biochemistry and Molecular Biology, Johns Hopkins University, Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
- Johns Hopkins Malaria Research Institute, Johns Hopkins University, Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Jamie L. Schlessman
- Chemistry Department, US Naval Academy, 572 Holloway Road, Annapolis, MD 21402, USA
| | - Matthew R. Preimesberger
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
| | - Jürgen Bosch
- Department of Biochemistry and Molecular Biology, Johns Hopkins University, Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
- Johns Hopkins Malaria Research Institute, Johns Hopkins University, Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Juliette T. J. Lecomte
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
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