Dssp The dominant search intent appears to be informational, focusing on understanding what peptide secondary structure is, its common forms, and how it's predicted or analyzed.
Tier 1:
* search_keyword: peptide secondary structure
* High-relevance phrases: polypeptide backbone, hydrogen bonding, alpha helix, beta pleated sheet, regular local sub-structures, predicting peptide secondary structures
Tier 2:
* Entities: Polypeptide, Protein, Amino acid residues
* Attributes/Variations: Alpha-helices, Beta-pleated sheets, Beta-turns, Polyproline, Beta helix
* Concepts: Tertiary structure, Quaternary structure, Electron transport, Conformational space, Peptide mimetics
* Analysis/Prediction: PEP-FOLD, PSSP-MVIRT, Circular Dichroism spectroscopy, DSSP, Ramachandran plots, Evolutionary methods
Tier 3:
* "Webservice for predicting secondary structure of peptides" (too tool-specific for a general overview)
* "Diversity of Secondary Structure in Catalytic Peptides" (too specific application)
* "Theoretical Analysis of Secondary Structures of β-Peptides" (too specific peptide type)
* "Secondary structure determines electron transport" (interesting but potentially too niche for a general introduction)
* "Explainable Deep Hypergraph Learning Modeling" (technical methodology)
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Peptide secondary structure refers to the arrangement of amino acid residues in regular, local sub-structures along the polypeptide backbone. These structures are primarily stabilized by hydrogen bonds that form between the amino hydrogen and carboxyl oxygen atoms of the peptide backbone. Understanding peptide secondary structure is fundamental to comprehending how proteins fold into their functional three-dimensional shapes.Levels of Protein Organization The most common types of secondary structures observed in peptides and proteins are the alpha ($\alpha$) helix and the beta ($\beta$) pleated sheet, though other forms like beta turns also play significant roles in shaping the overall protein architecture.
At its core, peptide secondary structure is defined by the patterns of hydrogen bonding within the polypeptide backbone. Unlike the primary structure, which is simply the linear sequence of amino acids, secondary structure describes the first level of local folding. This regular, local structure arises from the repetitive nature of the peptide bonds and the specific orientations that minimize energy within the polypeptide chain. These localized arrangements are crucial because they provide a framework upon which further folding into tertiary and quaternary structures can occur.
The landscape of peptide secondary structures is dominated by a few key motifs:
* Alpha ($\alpha$) Helix: This is a coiled, helical structure where the polypeptide backbone winds into a right-handed spiral. Hydrogen bonds form between the carbonyl oxygen of one amino acid residue and the amide hydrogen of the residue four positions down the chain. This arrangement makes the $\alpha$-helix a stable and common secondary structure element作者：Y Shen·2012·被引用次数：724—PEP-FOLD is a de novo approach aimed at predicting peptide structuresfrom amino acid sequences. This method, based on structural alphabet SA letters..
* Beta ($\beta$) Pleated Sheet: In contrast to the helix, $\beta$-pleated sheets are formed by segments of the polypeptide chain aligning side-by-side. These segments, called $\beta$-strands, can be arranged in parallel or antiparallel fashion.Peptide Secondary Structure Mimetics | Peptidomimeticos Hydrogen bonds form between adjacent strands, creating a flattened, sheet-like structure that can appear "pleated" due to the tetrahedral geometry of the alpha carbons.
* Beta ($\beta$) Turns: These are short, tight loops that typically reverse the direction of the polypeptide chain. They often connect $\alpha$-helices and $\beta$-strands, allowing the polypeptide to fold back on itself. $\beta$-turns are usually stabilized by a hydrogen bond between the first and fourth residue of the turn.
While these are the most prevalent, other secondary structures exist, such as polyproline helices, which are common in collagen, and various types of $\beta$-helices.Protein structure: Primary, secondary, tertiary & quatrenary ... The specific sequence of amino acids in a peptide or protein strongly influences which secondary structures are favored, as different residues have varying propensities to form helices or sheetsDespite of similar absorption spectra these proteins show significant differences in theirsecondary structure: hemoglobin is determined by an α-helix structure ....
Accurately predicting peptide secondary structures from their amino acid sequences is a significant area of research in bioinformatics. Tools like PEP-FOLD and PSSP-MVIRT utilize computational approaches, often incorporating evolutionary information and machine learning models, to forecast these local structures. These prediction methods are vital for understanding protein function and for designing novel peptides.Thesecondary structureis usually defined by the pattern of hydrogen bonds between the amino hydrogen and carboxyl oxygen atoms in thepeptidebackbone.
Experimental techniques also play a crucial role.The most common types of secondary structures are theα helix and the β pleated sheet. Both structures are held in shape by hydrogen bonds, which form between ... Circular Dichroism (CD) spectroscopy is a widely used method for quantifying secondary structure content in polypeptides by measuring the differential absorption of left and right circularly polarized light.作者：P Jana·2022·被引用次数：2—The tendency of a polypeptide chain (composed of polar and non‐polar amino acid residues) to form a particularsecondary structure, either α‐helical, β‐sheet‐ ... Other methods, such as X-ray crystallography and Nuclear Magnetic Resonance (NMR) spectroscopy, provide detailed atomic-level information about protein structure, including secondary structural elementsThe most common secondary structures areα-helices, β-pleated sheets, and β-turns. The α-helix is a right-handed helix with amino acid residues spaced at 3.6 .... Algorithms like DSSP (Dictionary of Protein Secondary Structure) are used to assign secondary structure types to residues based on these experimental or computationally derived three-dimensional coordinates2019年2月25日—In this study, 3107 unique peptides have been used to train, test and evaluatepeptide secondary structureprediction models..
The peptide secondary structure is not merely an intermediate step in protein folding; it directly influences a peptide's or protein's function. The specific arrangement of helices, sheets, and turns creates the local environment that can be critical for binding substrates, interacting with other molecules, or catalyzing reactions.Explainable Deep Hypergraph Learning Modeling the ... For instance, the secondary structure plays a key role in phenomena like electron transport in certain peptides. Furthermore, understanding secondary structures is essential for developing peptide mimetics, which are molecules designed to mimic or induce specific secondary structures for therapeutic or research purposes. The conformational space available to peptides allows for a surprising diversity in their potential structures and functions.
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