scholarly journals Stapling of two PEGylated side chains increases the conformational stability of the WW domain via an entropic effect

2018 ◽  
Vol 16 (46) ◽  
pp. 8933-8939 ◽  
Author(s):  
Qiang Xiao ◽  
Natalie A. Bécar ◽  
Nathaniel P. Brown ◽  
Mason S. Smith ◽  
Kimberlee L. Stern ◽  
...  
Keyword(s):  
Tertiary Structure ◽  
Conformational Stability ◽  
Side Chains ◽  
Primary Sequence ◽  
Ww Domain ◽  
Entropic Effect

PEGylation + stapling contributes more to conformational stability when the two linked sites are close in tertiary structure but far apart in primary sequence.

Insights into the Structural Features, Conformational Stability and Functional Activity of the Olneya tesota PF2 Lectin

2020 ◽  
Vol 27 ◽  
Author(s):  
Edgar Acedo-Espinoza ◽  
Irlanda Lagarda-Diaz ◽  
Rosina Cabrera ◽  
Ana M. Guzman-Partida ◽  
Amir Maldonado-Arce ◽  
...  
Keyword(s):  
Tertiary Structure ◽  
Proteolytic Enzymes ◽  
Conformational Stability ◽  
Structural Features ◽  
Beta Sheets ◽  
Hemagglutinating Activity ◽  
Effect Of Temperature ◽  
Hydrodynamic Diameter ◽  
Bioinformatic Tools ◽  
Structural Levels

Background: The O. tesota lectin PF2 is a tetrameric protein with subunits of 33 kDa that recognizes only complex carbohydrates, resistant to proteolytic enzymes and has insecticidal activity against Phaseolus beans pest. Objective: To explore PF2 lectin features at different protein structural levels and to evaluate the effect of temperature and pH on its functionality and conformational stability. Methods: PF2 lectin was purified by affinity chromatography. Its primary structure was resolved by mass spectrometry and analyzed by bioinformatic tools, including its tertiary structure homology modeling. The effect of temperature and pH on its conformational traits and stability was addressed by dynamic light scattering, circular dichroism, and intrinsic fluorescence. The hemagglutinating activity was evaluated using a suspension of peripheral blood erythrocytes. Results: The proposed PF2 folding comprises a high content of beta sheets. At pH 7 and 25 °C, the hydrodynamic diameter (Dh) was found to be 12.3 nm which corresponds to the oligomeric native state of PF2 lectin. Dh increased under the other evaluated pH and temperature conditions, suggesting protein aggregation. At basic pH, PF2 exhibited low conformational stability. The native PF2 (pH 7) retained its full hemagglutinating activity up to 45 °C and exhibited one transition state with a melting temperature of 76.8 °C. Conclusion: PF2 showed distinctive characteristics found in legume lectins. The pH influences the functionality and conformational stability of the protein. PF2 lectin displayed a relatively narrow thermostability to the loss of secondary structure and hemagglutinating activity.

scholarly journals PEGylation near a Patch of Nonpolar Surface Residues Increases the Conformational Stability of the WW Domain

2019 ◽  
Vol 85 (3) ◽  
pp. 1725-1730
Author(s):  
Steven R. E. Draper ◽  
Dallin S. Ashton ◽  
Benjamin M. Conover ◽  
Anthony J. Carter ◽  
Kimberlee L. Stern ◽  
...  
Keyword(s):  
Conformational Stability ◽  
Ww Domain

Impact of Site-Specific PEGylation on the Conformational Stability and Folding Rate of the Pin WW Domain Depends Strongly on PEG Oligomer Length

2013 ◽  
Vol 24 (5) ◽  
pp. 796-802 ◽  
Author(s):  
Brijesh K. Pandey ◽  
Mason S. Smith ◽  
Chad Torgerson ◽  
Paul B. Lawrence ◽  
Sam S. Matthews ◽  
...  
Keyword(s):  
Conformational Stability ◽  
Folding Rate ◽  
Site Specific ◽  
Ww Domain

scholarly journals Solution Structure of Synthetic Penaeidin-4 with Structural and Functional Comparisons with Penaeidin-3

2005 ◽  
Vol 280 (16) ◽  
pp. 16009-16018 ◽  
Author(s):  
Brandon J. Cuthbertson ◽  
Yinshan Yang ◽  
Evelyne Bachère ◽  
Erika E. Büllesbach ◽  
Paul S. Gross ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Solution Structure ◽  
Tertiary Structure ◽  
Structural Characteristics ◽  
Target Specificity ◽  
Primary Sequence ◽  
Specific Domain ◽  
Rich Domain ◽  
Isoform Diversity ◽  
Cysteine Rich Domain

Antimicrobial peptide structure has direct implications for the complexity of functions and mechanisms of action. The penaeidin antimicrobial peptide family from shrimp is divided into multiple class designations based on primary structure. The penaeidin classes are not only characterized by variability in primary sequence but also by variation in target specificity and effectiveness. Whereas class 4 exhibits low isoform diversity within species and is highly conserved between species, the primary sequence of penaeidin class 3 is less conserved between species and exhibits considerable isoform diversity within species. All penaeidins, regardless of class or species, are composed of two dramatically different domains: an unconstrained proline-rich domain and a disulfide bond-stabilized cysteine-rich domain. The proline-rich domain varies in length and is generally less conserved, whereas the spacing and specific residue content of the cysteine-rich domain is more conserved. The structure of the synthetic penaeidin class 4 (PEN4-1) fromLitopenaeus setiferuswas analyzed using several approaches, including chemical mapping of disulfide bonds, circular dichroism analysis of secondary structural characteristics, and complete characterization of the solution structure of the peptide by proton NMR.L. setiferusPEN4-1 was then compared with the previously characterized structure of penaeidin class 3 fromLitopenaeus vannamei. Moreover, the specificity of these antimicrobial peptides was examined through direct comparison of activity against a panel of microbes. The penaeidin classes differ in microbial target specificity, which correlates to variability in specific domain sequence. However, the tertiary structure of the cysteine-rich domain and indeed the overall structure of penaeidins are conserved across classes.

scholarly journals Hyperglutamylation of Tubulin Can either Stabilize or Destabilize Microtubules in the Same Cell

2009 ◽  
Vol 9 (1) ◽  
pp. 184-193 ◽  
Author(s):  
Dorota Wloga ◽  
Drashti Dave ◽  
Jennifer Meagley ◽  
Krzysztof Rogowski ◽  
Maria Jerka-Dziadosz ◽  
...  
Keyword(s):  
Chain Length ◽  
Eukaryotic Cells ◽  
Side Chain ◽  
Side Chains ◽  
Primary Sequence ◽  
Side Chain Length ◽  
Length Regulation ◽  
Cytoplasmic Microtubules

ABSTRACT In most eukaryotic cells, tubulin is subjected to posttranslational glutamylation, a conserved modification of unclear function. The glutamyl side chains form as branches of the primary sequence glutamic acids in two biochemically distinct steps: initiation and elongation. The length of the glutamyl side chain is spatially controlled and microtubule type specific. Here, we probe the significance of the glutamyl side chain length regulation in vivo by overexpressing a potent side chain elongase enzyme, Ttll6Ap, in Tetrahymena. Overexpression of Ttll6Ap caused hyperelongation of glutamyl side chains on the tubulin of axonemal, cortical, and cytoplasmic microtubules. Strikingly, in the same cell, hyperelongation of glutamyl side chains stabilized cytoplasmic microtubules and destabilized axonemal microtubules. Our observations suggest that the cellular outcomes of glutamylation are mediated by spatially restricted tubulin interactors of diverse nature.

scholarly journals Completion of the amino acid sequence of papain

1969 ◽  
Vol 114 (2) ◽  
pp. 279-288 ◽  
Author(s):  
S. S. Husain ◽  
G. Lowe
Keyword(s):  
Acetic Acid ◽  
Amino Acid ◽  
Hydrochloric Acid ◽  
Amino Acid Sequence ◽  
Tertiary Structure ◽  
Primary Sequence ◽  
Inhibited Enzyme

Papain was inhibited with bromo[2−14C]acetic acid, the tertiary structure of the inhibited enzyme was unfolded and the disulphide bridges were reduced with mercaptoethanol and aminoethylated. Digestion with trypsin gave a radioactive peptide consisting of residues 18–58 inclusive and containing therefore the sequence of the thirteen unknown residues 29–41 in the primary sequence of papain. This peptide was digested with pepsin to give a radioactive peptide consisting of residues 18–47, which after digestion with 0·4m-hydrochloric acid gave a radioactive peptide consisting of residues 24–43 inclusive. Further digestion with 6m-hydrochloric acid gave peptides that were used to determine the sequence: Ser-Ala-Val-Val-Thr-Ile-Glx-Gly-Ile-Ile-Lys-Ile-Arg for the residues 29–41, so completing the amino acid sequence of papain.

Amyloid structure

2014 ◽  
Vol 56 ◽  
pp. 1-10 ◽  
Author(s):  
Louise Serpell
Keyword(s):  
Hydrogen Bonding ◽  
Sequence Homology ◽  
Amyloid Fibrils ◽  
Side Chains ◽  
Primary Sequence ◽  
Sheet Structure ◽  
Β Sheets ◽  
The Stability ◽  
Β Sheet ◽  
Proteins And Peptides

Amyloid fibrils are formed by numerous proteins and peptides that share little sequence homology. The structures formed are highly ordered and extremely stable, being composed of β-sheet structure and stabilized along their length by hydrogen bonding. The fibrils are formed by several protofilaments that wind around one another in rope-like structures, lending further strength and stability to the resulting fibres. The fact that so many proteins and peptides form amyloid structures under suitable conditions, seems to suggest that the sequence of the precursor is unimportant. However, it is now clear that side chains play a central role in forming interactions between several β-sheets to further stabilize and regulate the structures. The primary sequence plays a central role in determining the rate of fibril formation, the stability of the resulting structure to degradation and the final morphology of the fibrils. The side chains regulate the elongation and growth, and also the lateral association of the protofilament and fibrils, having a significant impact on the final architecture.

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