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Benson DR, Deng B, Kashipathy MM, Lovell S, Battaile KP, Cooper A, Gao P, Fenton AW, Zhu H. The N-terminal intrinsically disordered region of Ncb5or docks with the cytochrome b 5 core to form a helical motif that is of ancient origin. Proteins 2024; 92:554-566. [PMID: 38041394 DOI: 10.1002/prot.26647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 11/10/2023] [Accepted: 11/17/2023] [Indexed: 12/03/2023]
Abstract
NADH cytochrome b5 oxidoreductase (Ncb5or) is a cytosolic ferric reductase implicated in diabetes and neurological conditions. Ncb5or comprises cytochrome b5 (b5 ) and cytochrome b5 reductase (b5 R) domains separated by a CHORD-Sgt1 (CS) linker domain. Ncb5or redox activity depends on proper inter-domain interactions to mediate electron transfer from NADH or NADPH via FAD to heme. While full-length human Ncb5or has proven resistant to crystallization, we have succeeded in obtaining high-resolution atomic structures of the b5 domain and a construct containing the CS and b5 R domains (CS/b5 R). Ncb5or also contains an N-terminal intrinsically disordered region of 50 residues that has no homologs in other protein families in animals but features a distinctive, conserved L34 MDWIRL40 motif also present in reduced lateral root formation (RLF) protein in rice and increased recombination center 21 in baker's yeast, all attaching to a b5 domain. After unsuccessful attempts at crystallizing a human Ncb5or construct comprising the N-terminal region naturally fused to the b5 domain, we were able to obtain a high-resolution atomic structure of a recombinant rice RLF construct corresponding to residues 25-129 of human Ncb5or (52% sequence identity; 74% similarity). The structure reveals Trp120 (corresponding to invariant Trp37 in Ncb5or) to be part of an 11-residue α-helix (S116 QMDWLKLTRT126 ) packing against two of the four helices in the b5 domain that surround heme (α2 and α5). The Trp120 side chain forms a network of interactions with the side chains of four highly conserved residues corresponding to Tyr85 and Tyr88 (α2), Cys124 (α5), and Leu47 in Ncb5or. Circular dichroism measurements of human Ncb5or fragments further support a key role of Trp37 in nucleating the formation of the N-terminal helix, whose location in the N/b5 module suggests a role in regulating the function of this multi-domain redox enzyme. This study revealed for the first time an ancient origin of a helical motif in the N/b5 module as reflected by its existence in a class of cytochrome b5 proteins from three kingdoms among eukaryotes.
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Affiliation(s)
- David R Benson
- Department of Chemistry, University of Kansas, Lawrence, Kansas, USA
| | - Bin Deng
- Department of Physical Therapy and Rehabilitation Science, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Maithri M Kashipathy
- Protein Structure and X-ray Crystallography Laboratory, The University of Kansas, Lawrence, Kansas, USA
| | - Scott Lovell
- Protein Structure and X-ray Crystallography Laboratory, The University of Kansas, Lawrence, Kansas, USA
| | | | - Anne Cooper
- Protein Production Group, The University of Kansas, Lawrence, Kansas, USA
| | - Philip Gao
- Protein Production Group, The University of Kansas, Lawrence, Kansas, USA
| | - Aron W Fenton
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Hao Zhu
- Department of Physical Therapy and Rehabilitation Science, University of Kansas Medical Center, Kansas City, Kansas, USA
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
- Department of Clinical Laboratory Sciences, University of Kansas Medical Center, Kansas City, Kansas, USA
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Hall R, Yuan S, Wood K, Katona M, Straub AC. Cytochrome b5 reductases: Redox regulators of cell homeostasis. J Biol Chem 2022; 298:102654. [PMID: 36441026 PMCID: PMC9706631 DOI: 10.1016/j.jbc.2022.102654] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022] Open
Abstract
The cytochrome-b5 reductase (CYB5R) family of flavoproteins is known to regulate reduction-oxidation (redox) balance in cells. The five enzyme members are highly compartmentalized at the subcellular level and function as "redox switches" enabling the reduction of several substrates, such as heme and coenzyme Q. Critical insight into the physiological and pathophysiological significance of CYB5R enzymes has been gleaned from several human genetic variants that cause congenital disease and a broad spectrum of chronic human diseases. Among the CYB5R genetic variants, CYB5R3 is well-characterized and deficiency in expression and activity is associated with type II methemoglobinemia, cancer, neurodegenerative disorders, diabetes, and cardiovascular disease. Importantly, pharmacological and genetic-based strategies are underway to target CYB5R3 to circumvent disease onset and mitigate severity. Despite our knowledge of CYB5R3 in human health and disease, the other reductases in the CYB5R family have been understudied, providing an opportunity to unravel critical function(s) for these enzymes in physiology and disease. In this review, we aim to provide the broad scientific community an up-to-date overview of the molecular, cellular, physiological, and pathophysiological roles of CYB5R proteins.
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Affiliation(s)
- Robert Hall
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Shuai Yuan
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Katherine Wood
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mate Katona
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Adam C Straub
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Center for Microvascular Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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Cui J, Chen H, Tang X, Zhang H, Chen YQ, Chen W. Characterization and Molecular Mechanism of a Novel Cytochrome b5 Reductase with NAD(P)H Specificity from Mortierella alpina. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:5186-5196. [PMID: 35416034 DOI: 10.1021/acs.jafc.1c08108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The electron-transfer capabilities of cytochrome b5 reductase (Cyt b5R) and NADPH supply have been shown to be critical factors in microbial fatty acid synthesis. Unfortunately, Cyt b5R substrate specificity is limited to the coenzyme NADH. In this study, we discovered that a novel Cyt b5R from Mortierella alpina (MaCytb5RII) displays affinity for NADPH and NADH. The enzymatic characteristics of high-purity MaCytb5RII were determined with the Km,NADPH and Km,NADH being 0.42 and 0.07 mM, respectively. MaCytb5RII shows high specific activity at 4 °C and pH 9.0. We anchored the residues that interacted with the coenzymes using the homology models of MaCytb5Rs docking NAD(P)H and FAD. The enzyme activity analysis of the purified mutants MaCytb5RII[S230N], MaCytb5RII[Y242F], and MaCytb5RII[S272A] revealed that Ser230 is essential for MaCytb5RII to have dual NAD(P)H dependence, whereas Tyr242 influences MaCytb5RII's NADPH affinity and Ala272 greatly decreases MaCytb5RII's NADH affinity.
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Affiliation(s)
- Jie Cui
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
| | - Xin Tang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi 214122, P. R. China
- Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi 214122, P. R. China
| | - Yong Q Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
- Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi 214122, P. R. China
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27127, United States
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi 214122, P. R. China
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Johnson JL. Mutations in Hsp90 Cochaperones Result in a Wide Variety of Human Disorders. Front Mol Biosci 2021; 8:787260. [PMID: 34957217 PMCID: PMC8694271 DOI: 10.3389/fmolb.2021.787260] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/08/2021] [Indexed: 12/19/2022] Open
Abstract
The Hsp90 molecular chaperone, along with a set of approximately 50 cochaperones, mediates the folding and activation of hundreds of cellular proteins in an ATP-dependent cycle. Cochaperones differ in how they interact with Hsp90 and their ability to modulate ATPase activity of Hsp90. Cochaperones often compete for the same binding site on Hsp90, and changes in levels of cochaperone expression that occur during neurodegeneration, cancer, or aging may result in altered Hsp90-cochaperone complexes and client activity. This review summarizes information about loss-of-function mutations of individual cochaperones and discusses the overall association of cochaperone alterations with a broad range of diseases. Cochaperone mutations result in ciliary or muscle defects, neurological development or degeneration disorders, and other disorders. In many cases, diseases were linked to defects in established cochaperone-client interactions. A better understanding of the functional consequences of defective cochaperones will provide new insights into their functions and may lead to specialized approaches to modulate Hsp90 functions and treat some of these human disorders.
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Affiliation(s)
- Jill L Johnson
- Department of Biological Sciences and Center for Reproductive Biology, University of Idaho, Moscow, ID, United States
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Dean ME, Johnson JL. Human Hsp90 cochaperones: perspectives on tissue-specific expression and identification of cochaperones with similar in vivo functions. Cell Stress Chaperones 2021; 26:3-13. [PMID: 33037995 PMCID: PMC7736379 DOI: 10.1007/s12192-020-01167-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/12/2020] [Accepted: 09/16/2020] [Indexed: 12/13/2022] Open
Abstract
The Hsp90 molecular chaperone is required for the function of hundreds of different cellular proteins. Hsp90 and a cohort of interacting proteins called cochaperones interact with clients in an ATP-dependent cycle. Cochaperone functions include targeting clients to Hsp90, regulating Hsp90 ATPase activity, and/or promoting Hsp90 conformational changes as it progresses through the cycle. Over the last 20 years, the list of cochaperones identified in human cells has grown from the initial six identified in complex with steroid hormone receptors and protein kinases to about fifty different cochaperones found in Hsp90-client complexes. These cochaperones may be placed into three groups based on shared Hsp90 interaction domains. Available evidence indicates that cochaperones vary in client specificity, abundance, and tissue distribution. Many of the cochaperones have critical roles in regulation of cancer and neurodegeneration. A more limited set of cochaperones have cellular functions that may be limited to tissues such as muscle and testis. It is likely that a small set of cochaperones are part of the core Hsp90 machinery required for the folding of a wide range of clients. The presence of more selective cochaperones may allow greater control of Hsp90 activities across different tissues or during development.
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Affiliation(s)
- Marissa E Dean
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844-3051, USA
| | - Jill L Johnson
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844-3051, USA.
- Center for Reproductive Biology, University of Idaho, Moscow, ID, 83844-3051, USA.
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