Temperature‐induced transition between polyproline I and II helices: quantitative fitting of hysteresis effects

Kuemin, Michael; Engel, Jürgen; Wennemers, Helma

doi:10.1002/psc.1245

Cited by 37 publications

(48 citation statements)

References 37 publications

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“…The PPII conformation is favored in relatively polar solvents, such as water. The PPI conformation is formed preferentially in less polar solvents, such as n -propanol [83]. The transition between these helices involves isomerization of the peptide bond.…”

Section: Effects On Peptide Conformationmentioning

confidence: 99%

4-Fluoroprolines: Conformational Analysis and Effects on the Stability and Folding of Peptides and Proteins

Newberry

Raines

2016

Topics in Heterocyclic Chemistry

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Proline is unique among proteinogenic amino acids because a pyrrolidine ring links its amino group to its side chain. This heterocycle constrains the conformations of the main chain and thus templates particular secondary structures. Proline residues undergo post-translational modification at the 4-position to yield 4-hydroxyproline, which is especially prevalent in collagen. Interest in characterizing the effects of this modification led to the use of 4-fluoroprolines to enhance inductive properties relative to the hydroxyl group of 4-hydroxyproline and to eliminate contributions from hydrogen bonding. The strong inductive effect of the fluoro group has three main consequences: enforcing a particular pucker upon the pyrrolidine ring, biasing the conformation of the preceding peptide bond, and accelerating cis/trans prolyl peptide bond isomerization. These subtle, yet reliable modulations make 4-fluoroproline–incorporation a complement to traditional genetic approaches for exploring structure–function relationships in peptides and proteins, as well as for endowing peptides and proteins with conformational stability.

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Section: Effects On Peptide Conformationmentioning

confidence: 99%

4-Fluoroprolines: Conformational Analysis and Effects on the Stability and Folding of Peptides and Proteins

Newberry

Raines

2016

Topics in Heterocyclic Chemistry

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“…The orientation of the peptide bond in polyproline is extremely sensitive to its environment [26–28]. In nonpolar solvents such as propanol, the peptide oligomer adopts the right-handed helical PPI structure in which every peptide bond orients adjacent pyrolidine rings into a cis configuration [27,29,30], as is shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Ion Mobility-Mass Spectrometry Reveals the Energetics of Intermediates that Guide Polyproline Folding

Shi

Holliday

Glover

et al. 2015

J. Am. Soc. Mass Spectrom.

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Proline favors trans-configured peptide bonds in native proteins. Although cis/trans configurations vary for non-native and unstructured states, solvent also influences these preferences. Water induces the all-cis right-handed polyproline-I (PPI) helix of polyproline to fold into the all-trans left-handed polyproline-II (PPII) helix. Our recent work has shown that this occurs via a sequential mechanism involving six resolved intermediates. Here, we use ion mobility-mass spectrometry to make the first detailed thermodynamic measurements of the folding intermediates, which inform us about how and why this transition occurs. It appears that early intermediates are energetically favorable due to hydration of the peptide backbone, while late intermediates are enthalpically unfavorable. However, folding continues, as the entropy of the system increases upon successive formation of each new structure. When PPII is immersed in 1-propanol, the PPII→PPI transition occurs, but this reaction occurs through a very different mechanism. Early on, the PPII population splits onto multiple pathways that eventually converge through a late intermediate that continues on to the folded PPI helix. Nearly every step is endothermic. Folding results from a stepwise increase in the disorder of the system, allowing a wide-scale search for a critical late intermediate. Overall, the data presented here allow us to establish the first experimentally-determined energy surface for biopolymer folding as a function of solution environment.

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“…As a result, interpretation of CD spectra for AcGXPNH 2 is not very obvious. Differential spectra between AcGXPNH 2 and AcGXGNH 2 reveal that Pro exists as a mixture of PII and PI (polyproline I) helices in AcGXPNH 2 41; thus CD spectra of AcGXPNH 2 reflect contributions from both X and Pro, contributions from X are expected to show the characteristic far-UV CD signature of a mixture of PII and β conformations, similar to those observed for AcGXGNH 2 .…”

Section: Resultsmentioning

confidence: 55%

Populations of the Minor α-Conformation in AcGXGNH2 and the α-Helical Nucleation Propensities

Zhou

Zhang

et al. 2016

Sci Rep

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Intrinsic backbone conformational preferences of different amino acids are important for understanding the local structure of unfolded protein chains. Recent evidence suggests α-structure is relatively minor among three major backbone conformations for unfolded proteins. The α-helices are the dominant structures in many proteins. For these proteins, how could the α-structures occur from the least in unfolded to the most in folded states? Populations of the minor α-conformation in model peptides provide vital information. Reliable determination of populations of the α-conformers in these peptides that exist in multiple equilibriums of different conformations remains a challenge. Combined analyses on data from AcGXPNH2 and AcGXGNH2 peptides allow us to derive the populations of PII, β and α in AcGXGNH2. Our results show that on average residue X in AcGXGNH2 adopt PII, β, and α 44.7%, 44.5% and 10.8% of time, respectively. The contents of α-conformations for different amino acids define an α-helix nucleation propensity scale. With derived PII, β and α-contents, we can construct a free energy-conformation diagram on each AcGXGNH2 in aqueous solution for the three major backbone conformations. Our results would have broad implications on early-stage events of protein folding.

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Temperature‐induced transition between polyproline I and II helices: quantitative fitting of hysteresis effects

Cited by 37 publications

References 37 publications

4-Fluoroprolines: Conformational Analysis and Effects on the Stability and Folding of Peptides and Proteins

4-Fluoroprolines: Conformational Analysis and Effects on the Stability and Folding of Peptides and Proteins

Ion Mobility-Mass Spectrometry Reveals the Energetics of Intermediates that Guide Polyproline Folding

Populations of the Minor α-Conformation in AcGXGNH2 and the α-Helical Nucleation Propensities

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