PRRVRLK

Product Name: PRRVRLK

Sequence: PRRVRLK

Purity: 95% 

Storage : Sealed storage, away from moisture and light, under nitrogen

CAS.NO.: 2088834-66-4

SMILES: CC(C)C[C@@H](C(=O)N[C@@H](CCCCN)C(=O)O)NC(=O)[C@H](CCCN=C(N)N)NC(=O)[C@H](C(C)C)NC(=O)[C@H](CCCN=C(N)N)NC(=O)[C@H](CCCN=C(N)N)NC(=O)[C@@H]1CCCN1

CHEMICAl FORMULA: C40H77N17O8

IUPACNAME: (2S)-6-amino-2-[[(2S)-2-[[(2S)-5-(diaminomethylideneamino)-2-[[(2S)-2-[[(2S)-5-(diaminomethylideneamino)-2-[[(2S)-5-(diaminomethylideneamino)-2-[[(2S)-pyrrolidine-2-carbonyl]amino]pentanoyl]amino]pentanoyl]amino]-3-methylbutanoyl]amino]pentanoyl]amino]-4-methylpentanoyl]amino]hexanoic acid

INCHIKEY: NNUQRWCIMHYXGY-FLMSMKGQSA-N

INCHI: InChI=1S/C40H77N17O8/c1-22(2)21-29(35(62)55-28(37(64)65)11-5-6-16-41)56-33(60)26(14-9-19-50-39(44)45)54-36(63)30(23(3)4)57-34(61)27(15-10-20-51-40(46)47)53-32(59)25(13-8-18-49-38(42)43)52-31(58)24-12-7-17-48-24/h22-30,48H,5-21,41H2,1-4H3,(H,52,58)(H,53,59)(H,54,63)(H,55,62)(H,56,60)(H,57,61)(H,64,65)(H4,42,43,49)(H4,44,45,50)(H4,46,47,51)/t24-,25-,26-,27-,28-,29-,30-/m0/s1

Molarmass: 924.15

Application: PRRVRLK is a synthetic peptide linker used for fusion protein construction and protein engineering research. Its short, defined amino acid sequence can function as a compact spacer between protein domains, helping improve structural separation, folding, accessibility, and functional display. PRRVRLK is useful for designing recombinant fusion proteins, peptide-linked biomolecules, and modular protein systems where linker composition may influence stability or biological activity. This peptide is widely applied in molecular biology, synthetic biology, peptide synthesis, bioconjugation research, and fusion protein development requiring a reliable peptide linker for controlled domain connection.

Current Research: Overview PRRVRLK is a short synthetic peptide linker that can be used to make fusion proteins. It is composed of seven amino acid residues: proline-arginine-arginine-valine-arginine-leucine-lysine. In fusion protein engineering, peptide linkers are used to connect two or more protein domains while helping preserve the structure and function of each component. Fusion proteins are widely used in biotechnology, molecular biology, drug discovery, immunology, cell biology, and protein engineering. They can combine binding domains, enzymes, reporter proteins, purification tags, targeting sequences, cytokines, antibody fragments, or therapeutic protein modules into one engineered construct. However, directly joining two protein domains without an appropriate linker can cause steric hindrance, misfolding, aggregation, reduced expression, or loss of biological activity. A peptide linker such as PRRVRLK provides a defined connecting sequence that may help improve domain spacing and construct performance. PRRVRLK is especially notable because it is a short, basic, arginine-rich linker. Unlike long glycine-serine linkers that mainly provide high flexibility, PRRVRLK contains several positively charged residues and hydrophobic residues within a compact sequence. This makes it useful as a candidate linker in fusion protein design, particularly when researchers want to evaluate how a short charged peptide segment affects folding, expression, solubility, activity, or domain accessibility. Structural Features of PRRVRLK The sequence of PRRVRLK contains the following residues: P – Proline R – Arginine R – Arginine V – Valine R – Arginine L – Leucine K – Lysine This composition gives PRRVRLK several important properties. First, the linker is rich in basic amino acids. It contains three arginine residues and one lysine residue, giving the sequence a strong positive charge under many common experimental conditions. This cationic character may influence solubility, electrostatic interactions, protein surface behavior, and interaction with negatively charged biomolecules or domains. Second, PRRVRLK begins with proline, a structurally distinctive amino acid. Proline can restrict peptide backbone flexibility because its side chain forms a ring with the backbone nitrogen. In linker design, proline-containing sequences may reduce excessive conformational freedom and help create a more defined local geometry than highly flexible glycine-rich linkers. Third, the sequence contains valine and leucine, two hydrophobic aliphatic residues. These residues may influence local structure, hydrophobic interactions, and linker behavior within a folded protein context. Their presence means PRRVRLK is not a purely hydrophilic spacer; rather, it combines basic and hydrophobic characteristics. Because of these features, PRRVRLK should not be treated as a neutral passive connector. It may actively influence the physical and biological properties of a fusion protein depending on the connected domains and expression system. Role in Fusion Protein Design PRRVRLK can be used as a peptide linker to make fusion proteins. In a fusion protein, the linker connects two functional domains into a single polypeptide chain. The purpose of the linker is to allow both domains to fold correctly and function as intended. A well-designed linker can improve fusion protein performance in several ways. It can provide sufficient distance between domains, reduce steric interference, improve solubility, increase expression yield, and preserve biological activity. In some cases, the linker can also influence protease sensitivity, intracellular localization, receptor binding, or domain orientation. PRRVRLK may be useful when a compact linker is needed. Since it contains only seven amino acids, it adds minimal length compared with longer flexible linkers. This can be advantageous when the fusion protein requires close positioning of domains or when excessive linker length could reduce stability or disrupt function. At the same time, the short length of PRRVRLK means it may not be suitable for every construct. Large protein domains, sterically demanding binding interfaces, or proteins requiring independent movement may need longer linkers. For this reason, PRRVRLK is best evaluated experimentally alongside alternative linker sequences. Comparison with Common Fusion Protein Linkers Fusion protein linkers are often classified as flexible, rigid, or cleavable. Flexible linkers commonly contain glycine and serine residues, such as repeated GGGGS motifs. These linkers provide conformational freedom and are often used when two domains need independent movement. Rigid linkers may contain proline-rich or helical sequences that maintain separation and reduce random motion. Cleavable linkers contain protease-sensitive or chemically responsive sequences that allow domains to separate under defined conditions. PRRVRLK differs from standard glycine-serine linkers because it is arginine-rich and positively charged. It may provide less neutral flexibility and more electrostatic influence. Compared with longer rigid helical linkers, PRRVRLK is much shorter and does not necessarily impose an extended helical structure. Instead, it may function as a compact charged linker that provides limited spacing while contributing basic residues to the fusion junction. This makes PRRVRLK a useful option in linker screening studies. Researchers often test multiple linker sequences to identify the one that gives the best expression, folding, binding activity, enzymatic activity, or stability. PRRVRLK can be included as a short basic linker candidate for comparison with flexible, rigid, and longer peptide linkers. Applications in Current Research PRRVRLK may be used in several areas of protein engineering and biotechnology research. In fusion protein construction, PRRVRLK can connect two functional protein domains within one recombinant expression construct. In domain-spacing optimization, it may be tested to determine whether a short linker improves or reduces activity compared with longer spacer sequences. In recombinant protein expression, PRRVRLK-containing constructs may be evaluated for effects on expression yield, folding, solubility, and aggregation. In structure-function studies, researchers can use PRRVRLK to examine how linker sequence and length influence domain orientation and biological performance. In protein interaction research, PRRVRLK may be useful in constructs where a binding domain is fused to an enzyme, reporter, affinity tag, or regulatory module. In therapeutic protein engineering, peptide linkers such as PRRVRLK may be evaluated during the design of multifunctional proteins, antibody fragments, cytokine fusions, receptor fusions, or targeted protein constructs. Importance of Linker Selection The linker is often a critical but underestimated part of a fusion protein. Even when the two functional domains are well characterized, the final fusion construct may fail if the linker is poorly designed. A linker that is too short may force domains too close together, causing steric hindrance or misfolding. A linker that is too long may reduce stability, allow unwanted flexibility, or alter effective concentration between domains. A linker with inappropriate charge or hydrophobicity may cause aggregation or nonspecific interactions. PRRVRLK provides a defined sequence that can be used to study these linker effects. Its compact size may help maintain close domain proximity, while its basic residues may influence protein surface charge and solubility. However, because it contains hydrophobic valine and leucine residues, researchers should also evaluate whether it affects aggregation or local folding in specific fusion proteins. The optimal linker depends on the biological system. A linker that performs well in one fusion protein may not work well in another. Therefore, PRRVRLK should be selected based on experimental goals and validated in the final construct. Research Considerations When using PRRVRLK to make fusion proteins, researchers should consider several factors. First, domain size and orientation are important. Large domains may require more spacing than PRRVRLK provides. Small domains or motifs may tolerate or benefit from a shorter linker. Second, charge effects should be evaluated. PRRVRLK contains multiple basic residues, which may improve solubility in some contexts but may also increase nonspecific binding to negatively charged molecules. Third, protein folding should be confirmed experimentally. The presence of a linker does not guarantee correct folding of both domains. Expression analysis, solubility testing, and functional assays are necessary. Fourth, cleavage or degradation risk should be assessed depending on the expression system. Peptide linkers can be exposed and accessible to proteases, especially when they connect independently folded domains. Fifth, comparative linker screening is recommended. PRRVRLK may be compared with glycine-serine linkers, proline-rich linkers, helical linkers, or longer charged linkers to determine the best design for a specific application. Analytical and functional evaluation may include SDS-PAGE, Western blotting, HPLC, LC-MS, size-exclusion chromatography, circular dichroism, thermal shift assays, enzyme activity assays, binding assays, and cell-based functional assays. Future Research Directions Fusion protein engineering continues to expand across biotechnology, medicine, and synthetic biology. As researchers design increasingly complex multifunctional proteins, linker choice becomes more important. Instead of relying only on traditional flexible linkers, current research increasingly explores linkers with defined charge, rigidity, length, and biological responsiveness. PRRVRLK may be useful in this broader effort as a short, basic peptide linker. Future studies may examine how PRRVRLK affects expression, folding, stability, activity, and intracellular behavior across different protein families. Researchers may also test modified versions of the sequence, such as longer PRRVRLK repeats, terminal extensions, charge-reduced variants, or combinations with glycine-serine spacers. Computational protein modeling and high-throughput linker screening may further help determine when PRRVRLK is an optimal choice. As fusion proteins become more sophisticated, compact linkers with specific physicochemical properties will remain valuable tools for fine-tuning protein architecture. Conclusion PRRVRLK is a short peptide linker that can be used to make fusion proteins. Its sequence contains proline, multiple arginine residues, valine, leucine, and lysine, giving it a compact, basic, and structurally distinctive profile. Unlike neutral glycine-serine linkers, PRRVRLK introduces positive charge and hydrophobic residues into the fusion junction, which may influence solubility, folding, domain orientation, and biological activity. In current research, PRRVRLK is useful as a linker candidate for fusion protein construction, recombinant protein engineering, domain-spacing optimization, and structure-function studies. Its performance should be validated in each fusion protein system, ideally through comparison with other linker sequences. As fusion protein design continues to evolve, PRRVRLK offers a practical short peptide linker for researchers developing multifunctional protein constructs.

Reference: Loew, A. (2024). U.S. Patent Application No. 18/251,848.