Although the relationship between molecular and supramolecular chirality remains elusive,the existing results have demonstrated the vital role of hydrophilic motifs in controlling the supramolecular handedness of pept...Although the relationship between molecular and supramolecular chirality remains elusive,the existing results have demonstrated the vital role of hydrophilic motifs in controlling the supramolecular handedness of peptide nanofibrils compared with hydrophobic ones.However,unlike conventional hydrophobic residues,we speculate that aromatic hydrophobic residues are mostly likely to play a unique role in regulating the supramolecular handedness because theπ–πstacking interactions of their side chains are directional like hydrogen bonding and can direct high levels of self-assembly due to the geometric confining of aromatic rings.To confirm this hypothesis,we here design a series of amphiphilic short peptides,with their hydrophobic motifs being composed of aromatic residues.Their short lengths not only favor their structural stability,synthesis,and sequence variation but also enable us to readily link their molecular and supramolecular structures.Through the combination of experiments and theoretical simulations,we demonstrate that the peptides containing L-form aromatic residues form left-handed nanofibrils while those containing D-form aromatic residues assemble into right-handed ones,irrespective of the chirality of their C-terminal hydrophilic residue.Theoretical calculations revealed that the stacking of aromatic side chains betweenβ-strands directed the twisting direction of theβ-sheets formed,with L-and D-form phenylalanine side chains stacking in a clockwise and anti-clockwise way,and more ordered and stronger aromatic stacking for homochiral peptides facilitated the formation of nanofibrils with a marked tubular feature.This study has bridged the knowledge gap in our understanding of how aromatic residues affect the supramolecular chirality of short peptides.展开更多
As a peptide hormone, CLV3 restricts the stem cell number in shoot apical meristem （SAM） by interacting with CLV1/CLV2/CRN/RPK2 receptor complexes. To elucidate how the function of the CLV3 peptide in SAM maintenanc...As a peptide hormone, CLV3 restricts the stem cell number in shoot apical meristem （SAM） by interacting with CLV1/CLV2/CRN/RPK2 receptor complexes. To elucidate how the function of the CLV3 peptide in SAM maintenance is established at the amino acid （AA） level, alanine substitutions were performed by introducing point mutations to individual residues in the peptide-coding region of CLV3 and its flanking sequences. Constructs carrying such substitutions, expressed under the control of CLV3 regulatory elements, were transformed to the clv3-2 null mutant to evaluate their efficiencies in complementing its defects in SAMs in vivo. These studies showed that aspartate-8, histidine-11, glycine-6, proline-4, arginine-1, and proline-9, arranged in an order of importance, were critical, while threonine-2, valine-3, serine-5, and the previously assigned hydroxylation and arabinosylation residue proline-7 were trivial for the endogenous CLV3 function in SAM maintenance. In contrast, substitutions of flanking residues did not impose much damage on CLV3. Complementation of different alanine-substituted constructs was confirmed by measurements of the sizes of SAMs and the WUS expression levels in transgenic plants. These studies established a complete contribution map of individual residues in the peptide-coding region of CLV3 for its function in SAM, which may help to understand peptide hormones in general.展开更多
基金the National Natural Science Foundation of China(Nos.22172193,22072181,and U1832108)a joint Innovate UK-Syngenta funded project under knowledge transfer partnership(No.KTP12697)an EPSRC IAA 377 grant(No.R128362)with Arxada.We acknowledge the use of the resources of the China Spallation Neutron Source in Dongguan of Guangdong Province of China.
文摘Although the relationship between molecular and supramolecular chirality remains elusive,the existing results have demonstrated the vital role of hydrophilic motifs in controlling the supramolecular handedness of peptide nanofibrils compared with hydrophobic ones.However,unlike conventional hydrophobic residues,we speculate that aromatic hydrophobic residues are mostly likely to play a unique role in regulating the supramolecular handedness because theπ–πstacking interactions of their side chains are directional like hydrogen bonding and can direct high levels of self-assembly due to the geometric confining of aromatic rings.To confirm this hypothesis,we here design a series of amphiphilic short peptides,with their hydrophobic motifs being composed of aromatic residues.Their short lengths not only favor their structural stability,synthesis,and sequence variation but also enable us to readily link their molecular and supramolecular structures.Through the combination of experiments and theoretical simulations,we demonstrate that the peptides containing L-form aromatic residues form left-handed nanofibrils while those containing D-form aromatic residues assemble into right-handed ones,irrespective of the chirality of their C-terminal hydrophilic residue.Theoretical calculations revealed that the stacking of aromatic side chains betweenβ-strands directed the twisting direction of theβ-sheets formed,with L-and D-form phenylalanine side chains stacking in a clockwise and anti-clockwise way,and more ordered and stronger aromatic stacking for homochiral peptides facilitated the formation of nanofibrils with a marked tubular feature.This study has bridged the knowledge gap in our understanding of how aromatic residues affect the supramolecular chirality of short peptides.
基金This work was supported by the Ministry of China （2007CB948200）, Chinese of Science and Technology Academy of Sciences （1105000003 and 200904910192008）, and the National Natural Science Foundation of China （30821007 and 31000623）. ACKNOWLEDGMENTS We thank Dr Trevor L. Wang at the John Innes Centre, UK, for critical reading of the manuscript Prof. Kexue Xu at the Institute of Botany, Chinese Academy of Sciences, for suggestions regarding the statistica~ data analysis and Dr Wei Gao at Beijing Forestry University for discussions of the results. No conflict of interest declared.
文摘As a peptide hormone, CLV3 restricts the stem cell number in shoot apical meristem （SAM） by interacting with CLV1/CLV2/CRN/RPK2 receptor complexes. To elucidate how the function of the CLV3 peptide in SAM maintenance is established at the amino acid （AA） level, alanine substitutions were performed by introducing point mutations to individual residues in the peptide-coding region of CLV3 and its flanking sequences. Constructs carrying such substitutions, expressed under the control of CLV3 regulatory elements, were transformed to the clv3-2 null mutant to evaluate their efficiencies in complementing its defects in SAMs in vivo. These studies showed that aspartate-8, histidine-11, glycine-6, proline-4, arginine-1, and proline-9, arranged in an order of importance, were critical, while threonine-2, valine-3, serine-5, and the previously assigned hydroxylation and arabinosylation residue proline-7 were trivial for the endogenous CLV3 function in SAM maintenance. In contrast, substitutions of flanking residues did not impose much damage on CLV3. Complementation of different alanine-substituted constructs was confirmed by measurements of the sizes of SAMs and the WUS expression levels in transgenic plants. These studies established a complete contribution map of individual residues in the peptide-coding region of CLV3 for its function in SAM, which may help to understand peptide hormones in general.
