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Scavuzzo-Duggan TR, Chaves AM, Singh A, Sethaphong L, Slabaugh E, Yingling YG, Haigler CH, Roberts AW. Cellulose synthase 'class specific regions' are intrinsically disordered and functionally undifferentiated. J Integr Plant Biol 2018; 60:481-497. [PMID: 29380536 DOI: 10.1111/jipb.12637] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 01/27/2018] [Indexed: 05/16/2023]
Abstract
Cellulose synthases (CESAs) are glycosyltransferases that catalyze formation of cellulose microfibrils in plant cell walls. Seed plant CESA isoforms cluster in six phylogenetic clades, whose non-interchangeable members play distinct roles within cellulose synthesis complexes (CSCs). A 'class specific region' (CSR), with higher sequence similarity within versus between functional CESA classes, has been suggested to contribute to specific activities or interactions of different isoforms. We investigated CESA isoform specificity in the moss, Physcomitrella patens (Hedw.) B. S. G. to gain evolutionary insights into CESA structure/function relationships. Like seed plants, P. patens has oligomeric rosette-type CSCs, but the PpCESAs diverged independently and form a separate CESA clade. We showed that P. patens has two functionally distinct CESAs classes, based on the ability to complement the gametophore-negative phenotype of a ppcesa5 knockout line. Thus, non-interchangeable CESA classes evolved separately in mosses and seed plants. However, testing of chimeric moss CESA genes for complementation demonstrated that functional class-specificity is not determined by the CSR. Sequence analysis and computational modeling showed that the CSR is intrinsically disordered and contains predicted molecular recognition features, consistent with a possible role in CESA oligomerization and explaining the evolution of class-specific sequences without selection for class-specific function.
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Affiliation(s)
- Tess R Scavuzzo-Duggan
- Department of Biological Sciences, University of Rhode Island, 120 Flagg Road, Kingston, RI, 02881, USA
| | - Arielle M Chaves
- Department of Biological Sciences, University of Rhode Island, 120 Flagg Road, Kingston, RI, 02881, USA
| | - Abhishek Singh
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Latsavongsakda Sethaphong
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Erin Slabaugh
- Department of Crop and Soil Sciences and Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Yaroslava G Yingling
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Candace H Haigler
- Department of Crop and Soil Sciences and Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Alison W Roberts
- Department of Biological Sciences, University of Rhode Island, 120 Flagg Road, Kingston, RI, 02881, USA
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Slabaugh E, Sethaphong L, Xiao C, Amick J, Anderson CT, Haigler CH, Yingling YG. Computational and genetic evidence that different structural conformations of a non-catalytic region affect the function of plant cellulose synthase. J Exp Bot 2014; 65:6645-53. [PMID: 25262226 PMCID: PMC4246192 DOI: 10.1093/jxb/eru383] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The β-1,4-glucan chains comprising cellulose are synthesized by cellulose synthases in the plasma membranes of diverse organisms including bacteria and plants. Understanding structure-function relationships in the plant enzymes involved in cellulose synthesis (CESAs) is important because cellulose is the most abundant component in the plant cell wall, a key renewable biomaterial. Here, we explored the structure and function of the region encompassing transmembrane helices (TMHs) 5 and 6 in CESA using computational and genetic tools. Ab initio computational structure prediction revealed novel bi-modal structural conformations of the region between TMH5 and 6 that may affect CESA function. Here we present our computational findings on this region in three CESAs of Arabidopsis thaliana (AtCESA1, 3, and 6), the Atcesa3(ixr1-2) mutant, and a novel missense mutation in AtCESA1. A newly engineered point mutation in AtCESA1 (Atcesa1(F954L) ) that altered the structural conformation in silico resulted in a protein that was not fully functional in the temperature-sensitive Atcesa1(rsw1-1) mutant at the restrictive temperature. The combination of computational and genetic results provides evidence that the ability of the TMH5-6 region to adopt specific structural conformations is important for CESA function.
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Affiliation(s)
- Erin Slabaugh
- Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Latsavongsakda Sethaphong
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Chaowen Xiao
- Department of Biology, the Pennsylvania State University, University Park, PA 16802, USA
| | - Joshua Amick
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Charles T Anderson
- Department of Biology, the Pennsylvania State University, University Park, PA 16802, USA
| | - Candace H Haigler
- Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Yaroslava G Yingling
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
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Kim HS, Ha SH, Sethaphong L, Koo YM, Yingling YG. The relationship between enhanced enzyme activity and structural dynamics in ionic liquids: a combined computational and experimental study. Phys Chem Chem Phys 2014; 16:2944-53. [DOI: 10.1039/c3cp52516c] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Singh A, Sethaphong L, Yingling YG. Structure Prediction of a Cellulose Synthase Protein and the Effect of Mutations. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1379] [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: 11/28/2022] Open
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Singh A, Sethaphong L, Yingling YG. Interactions of cations with RNA loop-loop complexes. Biophys J 2011; 101:727-35. [PMID: 21806941 DOI: 10.1016/j.bpj.2011.06.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 06/16/2011] [Accepted: 06/21/2011] [Indexed: 10/17/2022] Open
Abstract
RNA loop-loop interactions are essential in many biological processes, including initiation of RNA folding into complex tertiary shapes, promotion of dimerization, and viral replication. In this article, we examine interactions of metal ions with five RNA loop-loop complexes of unique biological significance using explicit-solvent molecular-dynamics simulations. These simulations revealed the presence of solvent-accessible tunnels through the major groove of loop-loop interactions that attract and retain cations. Ion dynamics inside these loop-loop complexes were distinctly different from the dynamics of the counterion cloud surrounding RNA and depend on the number of basepairs between loops, purine sequence symmetry, and presence of unpaired nucleotides. The cationic uptake by kissing loops depends on the number of basepairs between loops. It is interesting that loop-loop complexes with similar functionality showed similarities in cation dynamics despite differences in sequence and loop size.
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Affiliation(s)
- Abhishek Singh
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina, USA
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Sethaphong L, Yingling Y. Nucleic Acid Helical Conformation and Sequence Effects on Cationic Binding. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.631] [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: 10/18/2022] Open
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Singh A, Sethaphong L, Yingling YG. Molecular Dynamics and Distribution of Ions in Kissing Loop. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.1439] [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: 10/19/2022] Open
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Sethaphong L, Singh A, Marlowe AE, Yingling Y. Cationic Sequence Dependence in Nucleic Acid Structures. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.244] [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: 11/25/2022] Open
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Hustedt EJ, Stein RA, Sethaphong L, Brandon S, Zhou Z, Desensi SC. Dipolar coupling between nitroxide spin labels: the development and application of a tether-in-a-cone model. Biophys J 2006; 90:340-56. [PMID: 16214868 PMCID: PMC1367032 DOI: 10.1529/biophysj.105.068544] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Accepted: 09/26/2005] [Indexed: 11/18/2022] Open
Abstract
A tether-in-a-cone model is developed for the simulation of electron paramagnetic resonance spectra of dipolar coupled nitroxide spin labels attached to tethers statically disordered within cones of variable halfwidth. In this model, the nitroxides adopt a range of interprobe distances and orientations. The aim is to develop tools for determining both the distance distribution and the relative orientation of the labels from experimental spectra. Simulations demonstrate the sensitivity of electron paramagnetic resonance spectra to the orientation of the cones as a function of cone halfwidth and other parameters. For small cone halfwidths (< approximately 40 degrees ), simulated spectra are strongly dependent on the relative orientation of the cones. For larger cone halfwidths, spectra become independent of cone orientation. Tether-in-a-cone model simulations are analyzed using a convolution approach based on Fourier transforms. Spectra obtained by the Fourier convolution method more closely fit the tether-in-a-cone simulations as the halfwidth of the cone increases. The Fourier convolution method gives a reasonable estimate of the correct average distance, though the distance distribution obtained can be significantly distorted. Finally, the tether-in-a-cone model is successfully used to analyze experimental spectra from T4 lysozyme. These results demonstrate the utility of the model and highlight directions for further development.
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Affiliation(s)
- Eric J Hustedt
- Department of Molecular Physiology and Biophysics, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37232, USA.
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Pattanayek R, Sethaphong L, Pan C, Prhavc M, Prakash TP, Manoharan M, Egli M. Structural rationalization of a large difference in RNA affinity despite a small difference in chemistry between two 2'-O-modified nucleic acid analogues. J Am Chem Soc 2005; 126:15006-7. [PMID: 15547979 DOI: 10.1021/ja044637k] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chemical modification of nucleic acids at the 2'-position of ribose has generated antisense oligonucleotides (AONs) with a range of desirable properties. Electron-withdrawing substituents such as 2'-O-[2-(methoxy)ethyl] (MOE) confer enhanced RNA affinity relative to that of DNA by conformationally preorganizing an AON for pairing with the RNA target and by improving backbone hydration. 2'-Substitution of the ribose has also been shown to increase nuclease resistance and cellular uptake via changes in lipophilicity. Interestingly, incorporation of either 2'-O-[2-(methylamino)-2-oxoethyl]- (NMA) or 2'-O-(N-methylcarbamate)-modified (NMC) residues into AONs has divergent effects on RNA affinity. Incorporation of 2'-O-NMA-T considerably improves RNA affinity while incorporation of 2'-O-NMC-T drastically reduces RNA affinity. Crystal structures at high resolution of A-form DNA duplexes containing either 2'-O-NMA-T or 2'-O-NMC-T shed light on the structural origins of the surprisingly large difference in stability given the relatively minor difference in chemistry between NMA and NMC. NMA substituents adopt an extended conformation and use either their carbonyl oxygen or amino nitrogen to trap water molecules between phosphate group and sugar. The conformational properties of NMA and the observed hydration patterns are reminiscent of those found in the structures of 2'-O-MOE-modified RNA. Conversely, the carbonyl oxygen of NMC and O2 of T are in close contact, providing evidence that an unfavorable electrostatic interaction and the absence of a stable water structure are the main reasons for the loss in thermodynamic stability as a result of incorporation of 2'-O-NMC-modified residues.
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Affiliation(s)
- Rekha Pattanayek
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232, USA
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