Miniproteins simplify the protein-folding problem, allowing the dissection of forces that stabilize protein structures. Here we describe PPα-Tyr, a designed peptide comprising an α-helix buttressed by a polyproline II helix. PPα-Tyr is water soluble and monomeric, and it unfolds cooperatively with a midpoint unfolding temperature (T) of 39 °C. NMR structures of PPα-Tyr reveal proline residues docked between tyrosine side chains, as designed. The stability of PPα is sensitive to modifications in the aromatic residues: replacing tyrosine with phenylalanine, i.e., changing three solvent-exposed hydroxyl groups to protons, reduces the T to 20 °C. We attribute this result to the loss of CH-π interactions between the aromatic and proline rings, which we probe by substituting the aromatic residues with nonproteinogenic side chains. In analyses of natural protein structures, we find a preference for proline-tyrosine interactions over other proline-containing pairs, and observe abundant CH-π interactions in biologically important complexes between proline-rich ligands and SH3 and similar domains.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5860740 | PMC |
| http://dx.doi.org/10.1038/nchembio.2380 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A Model of Zymogen Factor XII: Insights into Protease Activation.
Blood Adv
January 2025
Vanderbilt University Medical Center, Nashville, Tennessee, United States.
In plasma, the zymogens factor XII (FXII) and prekallikrein reciprocally convert each other to the proteases FXIIa and plasma kallikrein (PKa). PKa cleaves high-molecular-weight kininogen (HK) to release bradykinin, which contributes to regulation of blood vessel tone and permeability. Plasma FXII is normally in a "closed" conformation that limits activation by PKa.
View Article and Find Full Text PDFReactions of SleC, Its Structure and Inhibition in Mitigation of Spore Germination in .
J Am Chem Soc
January 2025
Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Spore germination in is initiated by a cascade of activities of several proteins that culminates in the activation of SleC, a cell-wall-processing enzyme. We report herein the details of the enzymatic activities of SleC by the use of synthetic peptidoglycan fragments and of spore sacculi. The reactions include the formation of 1,6-anhydromuramate─a hallmark of lytic transglycosylase activity─as well as a muramate hydrolytic product, both of which proceed through the same transient oxocarbenium species.
View Article and Find Full Text PDFBiomimetic Silk Nanoparticle Manufacture: Calcium Ion-Mediated Assembly.
ACS Biomater Sci Eng
January 2025
Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral St., Glasgow G4 0RE,Scotland,U.K.
Silk has emerged as an interesting candidate among protein-based nanocarriers due to its favorable properties, including biocompatibility and a broad spectrum of processing options to tune particle critical quality attributes. The silk protein conformation during storage in the middle silk gland of the silkworm is modulated by various factors, including the most abundant metallic ion, calcium ion (Ca). Here, we report spiking of liquid silk with calcium ions to modulate the silk nanoparticle size.
View Article and Find Full Text PDFDesign of a light and Ca switchable organic-peptide hybrid.
Proc Natl Acad Sci U S A
February 2025
SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea.
The design of organic-peptide hybrids has the potential to combine our vast knowledge of protein design with small molecule engineering to create hybrid structures with complex functions. Here, we describe the computational design of a photoswitchable Ca-binding organic-peptide hybrid. The designed molecule, designated Ca-binding switch (CaBS), combines an EF-hand motif from classical Ca-binding proteins such as calmodulin with a photoswitchable group that can be reversibly isomerized between a spiropyran (SP) and merocyanine (MC) state in response to different wavelengths of light.
View Article and Find Full Text PDFRational design and modular synthesis of biodegradable ionizable lipids via the Passerini reaction for mRNA delivery.
Proc Natl Acad Sci U S A
February 2025
Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada.
The ionizable lipid component of lipid nanoparticle (LNP) formulations is essential for mRNA delivery by facilitating endosomal escape. Conventionally, these lipids are synthesized through complex, multistep chemical processes that are both time-consuming and require significant engineering. Furthermore, the development of new ionizable lipids is hindered by a limited understanding of the structure-activity relationships essential for effective mRNA delivery.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!