Glycosidicbond The trans peptide bond is the predominant configuration in biological systems, a fundamental aspect of protein structure and function.cis and trans Configurations of the Peptide Bond in N ... While the peptide bond itself is planar and rigid due to its partial double-bond character, it can exist in two geometric forms: *cis* and *trans*. Understanding these configurations is crucial for comprehending protein folding, stability, and biological activity作者：LA LaPlanche·1964·被引用次数：436—Cis/TransIsomerization in Secondary Amides: Reaction Paths, Nitrogen Inversion, and Relevance to Peptidic Systems..
In naturally occurring proteins, the vast majority of peptide bonds are found in the trans configuration. This preference is so strong that it's estimated that over 99.Peptide Bond Essentials - Biochemistry Flashcards9% of peptide bonds in proteins adopt this arrangement. In the trans conformation, the alpha-carbon atoms of the adjacent amino acid residues lie on opposite sides of the peptide bond. This spatial arrangement is energetically more favorable, primarily due to reduced steric hindrance between the side chains of the amino acid residues. The partial double bond character of the peptide bond restricts rotation around the C-N bond, contributing to its planarity and rigidityab initio study on small peptide model compound. This planarity is essential for maintaining the ordered secondary structures of proteins, such as alpha-helices and beta-sheetscis peptide bonds in proteins.
The distinction between *cis* and *trans* configurations lies in the relative positions of the alpha-carbon atoms across the peptide bond.作者：LA LaPlanche·1964·被引用次数：436—Cis/TransIsomerization in Secondary Amides: Reaction Paths, Nitrogen Inversion, and Relevance to Peptidic Systems.
* Trans Peptide Bond: The alpha-carbons are positioned on opposite sides of the C-N bond. This conformation minimizes steric clashes between amino acid side chains, making it the more stable and prevalent form in proteins.
* Cis Peptide Bond: The alpha-carbons are on the same side of the C-N bondIs peptide bond cis/trans isomerization a key stage in the .... This configuration can lead to significant steric repulsion between side chains, especially for larger amino acid residues. Consequently, cis peptide bonds are energetically less favorable and much rarer in proteins.
A notable exception to the overwhelming preference for the trans configuration involves proline residues. When proline is the amino acid following the peptide bond (iIs peptide bond cis/trans isomerization a key stage in the ....ePeptide Bond - an overview., the carboxyl group of the preceding amino acid forms a bond with the amino group of proline), the peptide bond can exist in either cis or trans forms with a much smaller energy difference between them.作者：S Banerjee·2024—TransPro on the other hand,is extensively stabilized by various local intramolecular non-covalent interactionsincluding the γ-turn H-bond [11], β-turn H-bond ... This is because proline's side chain forms a ring structure that connects back to its amino group, altering the steric landscape.作者：HA Baldoni·2000·被引用次数：51—Clearly, the ring must be of a certain size before atrans peptide bondmay be formed without a major ring strain. The question of cis–trans-isomerization ... While trans proline peptide bonds are still more common, cis proline peptide bonds occur more frequently than cis bonds involving other amino acids. The interconversion between cis and trans conformations of proline peptide bonds can play a significant role in protein folding pathways and the regulation of protein activity.
While the trans configuration is dominant, the existence and interconversion between cis and trans states are not merely structural curiosities. The slow rotation around the peptide bond, known as cis-trans isomerization, can be a rate-limiting step in protein folding and can influence the biological activity of proteins. Enzymes called peptidyl prolyl cis-trans isomerases (PPIases) catalyze this isomerization, particularly for proline peptide bonds, thereby facilitating protein folding and refolding processesCis and trans confi guration of peptide bond. A .... This isomerization is critical for the proper functioning of many proteins, and its regulation is essential for cellular processes.
The planarity and rigidity of the peptide bond, along with the geometric preference for the trans configuration, are foundational to the predictable folding of polypeptide chains into functional three-dimensional structuresDoes the cis/trans configuration of peptide bonds in .... While cis peptide bonds are rare, their presence, especially around proline residues, can introduce kinks or specific turns in the polypeptide chain, influencing protein conformation and interactions. Understanding these conformational possibilities is vital for fields ranging from biochemistry and molecular biology to drug design and protein engineering.
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