scholarly journals Opposite Regulatory Effects of Immobilized Cations on the Folding Vs. Assembly of Melittin

2021 ◽  
Vol 9 ◽  
Author(s):  
Lanlan Yu ◽  
Zhun Deng ◽  
Wenbo Zhang ◽  
Shuli Liu ◽  
Feiyi Zhang ◽  
...  
Keyword(s):  
Protein Structure ◽  
Hydrophobic Interactions ◽  
Noncovalent Interactions ◽  
Bulk Solution ◽  
Side Chain ◽  
Hofmeister Series ◽  
Helical Bundle ◽  
Regulatory Effects ◽  
Α Helix ◽  
Structure Breaking

Ions are crucial in modulating the protein structure. For the free ions in bulk solution, ammonium is kosmotropic (structure forming) and guanidinium is chaotropic (structure breaking) to the protein structure within the Hofmeister series. However, the effect of immobilized ions on a protein surface is less explored. Herein, we explored the influence of two immobilized cations (ammonium in the side chain of lysine and guanidinium in the side chain of arginine) on the folding and assembly of melittin. Melittin adopts an α-helix structure and is driven by hydrophobic interactions to associate into a helical bundle. To test the influence of immobilized cations on the peptide structure, we designed the homozygous mutants exclusively containing ammonium (melittin-K) or guanidinium (melittin-R) and compared the differences of melittin-K vs. melittin-R in their folding, assembly, and molecular functions. The side chains of lysine and arginine differ in their influences on the folding and assembly of melittin. Specifically, the side chain of R increases the α-helical propensity of melittin relative to that of K, following an inverse Hofmeister series. In contrast, the side chain of K favors the assembly of melittin relative to the side chain of R in line with a direct Hofmeister series. The opposite regulatory effects of immobilized cations on the folding and assembly of melittin highlight the complexity of the noncovalent interactions that govern protein intermolecular architecture.

Structure, stability and folding of the α-helix

2001 ◽  
Vol 68 ◽  
pp. 95-110 ◽  
Author(s):  
Andrew J. Doig ◽  
Charles D. Andrew ◽  
Duncan A. E. Cochran ◽  
Eleri Hughes ◽  
Simon Penel ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Hydrophobic Interactions ◽  
Data Bank ◽  
Site Directed Mutagenesis ◽  
Model Systems ◽  
Side Chain ◽  
Structure Stability ◽  
Helical Peptides ◽  
Vast Number ◽  
Α Helix

Pauling first described the α-helix nearly 50 years ago, yet new features of its structure continue to be discovered, using peptide model systems, site-directed mutagenesis, advances in theory, the expansion of the Protein Data Bank and new experimental techniques. Helical peptides in solution form a vast number of structures, including fully helical, fully coiled and partly helical. To interpret peptide results quantitatively it is essential to use a helix/coil model that includes the stabilities of all these conformations. Our models now include terms for helix interiors, capping, side-chain interactions, N-termini and 310-helices. The first three amino acids in a helix (N1, N2 and N3) and the preceding N-cap are unique, as their amide NH groups do not participate in backbone hydrogen bonding. We surveyed their structures in proteins and measured their amino acid preferences. The results are predominantly rationalized by hydrogen bonding to the free NH groups. Stabilizing side-chain-side-chain energies, including hydrophobic interactions, hydrogen bonding and polar/non-polar interactions, were measured accurately in helical peptides. Helices in proteins show a preference for having approximately an integral number of turns so that their N- and C-caps lie on the same side. There are also strong periodic trends in the likelihood of terminating a helix with a Schellman or αL C-cap motif. The kinetics of α-helix folding have been studied with stopped-flow deep ultraviolet circular dichroism using synchrotron radiation as the light source; this gives a far superior signal-to-noise ratio than a conventional instrument. We find that poly(Glu), poly(Lys) and alanine-based peptides fold in milliseconds, with longer peptides showing a transient overshoot in helix content.

Stabilization of protein structure by interaction of α-helix dipole with a charged side chain

Nature ◽  
1988 ◽  
Vol 335 (6192) ◽  
pp. 740-743 ◽  
Author(s):  
Das̆a S˘ali ◽  
Mark Bycroft ◽  
Alan R. Fersht
Keyword(s):  
Protein Structure ◽  
Side Chain ◽  
Α Helix

scholarly journals Pontocerebellar hypoplasia due to bi-allelic variants in MINPP1

2020 ◽  
Author(s):  
Bart Appelhof ◽  
Matias Wagner ◽  
Julia Hoefele ◽  
Anja Heinze ◽  
Timo Roser ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Hydrophobic Interactions ◽  
Inositol Phosphates ◽  
Side Chain ◽  
Globular Domain ◽  
Pontocerebellar Hypoplasia ◽  
Disease Mechanism ◽  
Nonsense Mediated Decay ◽  
Inositol Phosphatase ◽  
Induced Apoptosis

Abstract Pontocerebellar hypoplasia (PCH) describes a group of rare heterogeneous neurodegenerative diseases with prenatal onset. Here we describe eight children with PCH from four unrelated families harboring the homozygous MINPP1 (NM_004897.4) variants; c.75_94del, p.(Leu27Argfs*39), c.851 C > A, p.(Ala284Asp), c.1210 C > T, p.(Arg404*), and c.992 T > G, p.(Ile331Ser). The homozygous p.(Leu27Argfs*39) change is predicted to result in a complete absence of MINPP1. The p.(Arg404*) would likely lead to a nonsense mediated decay, or alternatively, a loss of several secondary structure elements impairing protein folding. The missense p.(Ala284Asp) affects a buried, hydrophobic residue within the globular domain. The introduction of aspartic acid is energetically highly unfavorable and therefore predicted to cause a significant reduction in protein stability. The missense p.(Ile331Ser) affects the tight hydrophobic interactions of the isoleucine by the disruption of the polar side chain of serine, destabilizing the structure of MINPP1. The overlap of the above-mentioned genotypes and phenotypes is highly improbable by chance. MINPP1 is the only enzyme that hydrolyses inositol phosphates in the endoplasmic reticulum lumen and several studies support its role in stress induced apoptosis. The pathomechanism explaining the disease mechanism remains unknown, however several others genes of the inositol phosphatase metabolism (e.g., INPP5K, FIG4, INPP5E, ITPR1) are correlated with phenotypes of neurodevelopmental disorders. Taken together, we present MINPP1 as a novel autosomal recessive pontocerebellar hypoplasia gene.

Stabilising Non-Polar/Polar Side Chain Interactions in the α-Helix

2000 ◽  
Vol 28 (3) ◽  
pp. A72-A72
Author(s):  
Charles D. Andrew ◽  
Simon Penel ◽  
Gareth R. Jones ◽  
Andrew J. Doig
Keyword(s):  
Side Chain ◽  
Α Helix

scholarly journals (De)stabilization of Alpha-Synuclein Fibrillary Aggregation by Charged and Uncharged Surfactants

2021 ◽  
Vol 22 (22) ◽  
pp. 12509
Author(s):  
Joana Angélica Loureiro ◽  
Stéphanie Andrade ◽  
Lies Goderis ◽  
Ruben Gomez-Gutierrez ◽  
Claudio Soto ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Hydrophobic Interactions ◽  
Neurodegenerative Disorder ◽  
Sodium Dodecyl ◽  
Lewy Bodies ◽  
Alpha Synuclein ◽  
Cetyltrimethylammonium Chloride ◽  
Α Helix ◽  
Β Sheet

Parkinson’s disease (PD) is the second most common neurodegenerative disorder. An important hallmark of PD involves the pathological aggregation of proteins in structures known as Lewy bodies. The major component of these proteinaceous inclusions is alpha (α)-synuclein. In different conditions, α-synuclein can assume conformations rich in either α-helix or β-sheets. The mechanisms of α-synuclein misfolding, aggregation, and fibrillation remain unknown, but it is thought that β-sheet conformation of α-synuclein is responsible for its associated toxic mechanisms. To gain fundamental insights into the process of α-synuclein misfolding and aggregation, the secondary structure of this protein in the presence of charged and non-charged surfactant solutions was characterized. The selected surfactants were (anionic) sodium dodecyl sulphate (SDS), (cationic) cetyltrimethylammonium chloride (CTAC), and (uncharged) octyl β-D-glucopyranoside (OG). The effect of surfactants in α-synuclein misfolding was assessed by ultra-structural analyses, in vitro aggregation assays, and secondary structure analyses. The α-synuclein aggregation in the presence of negatively charged SDS suggests that SDS-monomer complexes stimulate the aggregation process. A reduction in the electrostatic repulsion between N- and C-terminal and in the hydrophobic interactions between the NAC (non-amyloid beta component) region and the C-terminal seems to be important to undergo aggregation. Fourier transform infrared spectroscopy (FTIR) measurements show that β-sheet structures comprise the assembly of the fibrils.

scholarly journals Methyl side-chain dynamics prediction based on protein structure

2009 ◽  
Vol 25 (19) ◽  
pp. 2552-2558 ◽  
Author(s):  
Pablo Carbonell ◽  
Antonio del Sol
Keyword(s):  
Protein Structure ◽  
Side Chain ◽  
Chain Dynamics ◽  
Side Chain Dynamics

scholarly journals LK peptide side chain dynamics at interfaces are independent of secondary structure

2017 ◽  
Vol 19 (42) ◽  
pp. 28507-28511 ◽  
Author(s):  
Michael A. Donovan ◽  
Helmut Lutz ◽  
Yeneneh Y. Yimer ◽  
Jim Pfaendtner ◽  
Mischa Bonn ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Real Time ◽  
Surface Interactions ◽  
Side Chain ◽  
Chain Dynamics ◽  
Air Interface ◽  
Time Observation ◽  
Α Helix ◽  
Side Chain Dynamics ◽  
Real Time Observation

Real-time observation of the ultrafast motions of leucine side chains within model peptides at the water–air interface with representative folds – α-helix, 310-helix, β-strand – show that interfacial dynamics are mostly determined by surface interactions.

scholarly journals Enhancement of α-Helix Mimicry by an α/β-Peptide Foldamer via Incorporation of a Dense Ionic Side-Chain Array

2012 ◽  
Vol 134 (17) ◽  
pp. 7317-7320 ◽  
Author(s):  
Lisa M. Johnson ◽  
David E. Mortenson ◽  
Hyun Gi Yun ◽  
W. Seth Horne ◽  
Thomas J. Ketas ◽  
...  
Keyword(s):  
Side Chain ◽  
Α Helix
Sign in / Sign up

Export Citation Format

Share Document