Characterisation of pH dependent peptide nanostructures using small angle scattering

Vadakkedath, Praveen G.; McGillivray, Duncan J.

doi:10.1088/1742-6596/1537/1/012014

Cited by 1 publication

(1 citation statement)

References 19 publications

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“…At 5 mg mL −1 , the spectra exhibited random‐coil structure with a minimum in the 195–200 nm range (Figure S4, Supporting Information). Compared to Pvfp‐5‐Tyr, Pvfp‐5‐Dopa displayed a negative shoulder peak around 225 nm that can be attributed to the Dopa side‐chain, as recently reported for Dopa‐rich short peptides, [ 26 ] and the main negative peak of Pvfp‐5‐Dopa was also slightly shifted to a higher wavelength of the disordered region. Therefore, introducing Dopa instead of Tyr appears to only slightly influence the secondary structure of Pvfp‐5β.…”

Section: Resultssupporting

confidence: 75%

Liquid–Liquid Phase Separation of the Green Mussel Adhesive Protein Pvfp‐5 is Regulated by the Post‐Translated Dopa Amino Acid

Deepankumar

Guo

Mohanram³

et al. 2021

Advanced Materials

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The catecholic Dopa side-chain indeed exhibits versatile physicochemical features that makes it well-suited to adsorb and adhere to immersed substrates, including the ability to engage into numerous types of intermolecular interactions such as coordination bonding, [2,5] hydrogen bonding, [6] and hydrophobic interactions. [7] While there has been undeniable success in synthesizing catechol-containing polymers for enhanced water-resistant adhesives and coatings, [8,9] recent investigations have indicated that this Dopa "paradigm" of mussel adhesion may be subtler than previously proposed. Notably, both nano-scale and macroscopic adhesion studies of recombinant MFPs and MFP-derived peptides from the adhesive plaque-the section of the byssus in direct contact with substrates-have indicated that comparable levels of adhesion can be achieved even when tyrosine residues (Tyr) are not post-translated into Dopa. In particular for the Asian green mussel (Perna viridis), Bilotto et al. [10] reported surface force apparatus (SFA) adhesion measurements of the foot protein 5 (Pvfp-5β) [11] containing either Tyr or with most Tyr substituted to Dopa, and did not find statistically-significant differences of adhesion strengths and energies between the two variants. Likewise, Ou et al. [12] -also using Pvfp-5β as a model mussel adhesive protein-measured equivalent macroscopic adhesive strength values for Pvfp-5β when Tyr was enzymatically modified to Dopa. These results can be reconciled by the study of Maier et al. [13] together with molecular dynamic (MD) simulations by Ou et al. [12] The former reported that hydrated ions on oxide surfaces are evicted by Lys residues, enabling adjacent Dopa residues to form bidentate H-bonding with the oxide surface unimpeded by these hydrated ions, whereas the latter predicted that the reverse stepwise process, namely initial eviction of surface ions by aromatic residues followed by electrostatic binding of positively-charged residues, was also possible. Importantly, MD simulations revealed that Tyr is equally efficient at sweeping the surface of hydrated ions, thus eliminating their screening effect and enabling adjacent Lys residues to bind to the surface via electrostatic interactions. In addition, The underwater adhesive prowess of aquatic mussels has been largely attributed to the abundant post-translationally modified amino acid l-3,4-dihydroxyphenylalanine (Dopa) in mussel foot proteins (MFPs) that make up their adhesive threads. More recently, it has been suggested that during thread fabrication, MFPs form intermediate fluidic phases such as liquid crystals or coacervates regulated by a liquid-liquid phase separation (LLPS) process. Here, it is shown that Dopa plays another central role during mussel fiber formation, by enabling LLPS of Pvfp-5β, a main MFP of the green mussel Perna viridis. Using residue-specific substitution of Tyrosine (Tyr) for Dopa during recombinant expression, Dopa-substituted Pvfp-5β is shown to exhibit LLPS under seawater-like conditions, whereas the Tyr-only ...

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Section: Resultssupporting

confidence: 75%