Smart metallopoly(l-glutamic acid) polymers: reversible helix-to-coil transition at neutral pH

Abstract

Coordination to Zn species can be reversibly used to control the helix-to-coil transition of synthetic poly(l-glutamic acid) polymers at a neutral pH of 7.

Self-Assembly of Stimuli-Responsive Biohybrid Synthetic-b-Recombinant Block Copolypeptides

“…It has been established that this procedure did not alter the structure of the block copolymers. 64 The success of the reaction was confirmed by 1 to 7,900 g.mol -1 corresponding to total molar masses between 20,000 and 24,900 g.mol -1 , as summarized in Table 1. The weight ratios of poly(L-glutamic acid) in the copolypeptides are 15, 25 and 32 % respectively, these values allowing to scan a range of ratios driving the selfassembly.…”

“…The benzyl groups of the PBLG block were removed under mild acidic conditions as previously reported by Bonduelle and co-workers. 64…”

Smart Poly(imidazoyl-l-lysine): Synthesis and Reversible Helix-to-Coil Transition at Neutral pH

“…As depicted in Figure 2 , CD spectra were recorded between 195 and 255 nm at different pH values between 4 and 7. In marked contrast to the spectra of PL (dashed line at pH 7), the spectra of PIL revealed significant changes in CD with the appearance of minimum values that were attributable to an alpha helix structure [ 16 ]. Overall, the CD signature of the helix displayed a significant smaller 208 nm minimum and a slight red shifted n–π * peak at 225 nm (as compared to 222 nm) that previous work have attributed to the occurrence of alpha helix nanoaggregation [ 27 , 28 ].…”

“…For instance, helix to coil transitions can be controlled by means of pH changes for poly( l -glutamic acid) PGA [ 7 , 8 ] and poly ( l -lysine) PL [ 9 ]. Recent developments in this direction include the use of polypeptide polymers to enable a structuring switch upon biologically relevant stimuli changes [ 1 , 10 , 11 , 12 , 13 ], including redox changes [ 14 , 15 ], metal coordination [ 16 ] or DNA binding [ 17 ].…”

Confinement Effects on Polymer Dynamics: Thermo-Responsive Behaviours of Hydroxypropyl Cellulose Polymers in Phospholipid-Coated Droplets (Water-in-Oil Emulsion)

“…In the 1970s, it was revealed that coil-globule transition of a single polymer chain was induced by various stimuli such as change of solvent composition [ 10 ]. Helix-coil transitions of biopolymers has been also studied for many years [ 11 , 12 , 13 ]. Phase separation of polymers has been reported, in addition to the phase transition [ 14 , 15 ].…”