Site-specific PEGylation is an important strategy for enhancing the pharmacokinetic properties of protein drugs, and has been enabled by the recent development of many chemoselective reactions for protein side-chain modification. However, the impact of these different conjugation strategies on the properties of PEG-protein conjugates is poorly understood. Here we show that the ability of PEG to enhance protein conformational stability depends strongly on the identity of the PEG-protein linker, with the most stabilizing linkers involving conjugation of PEG to planar polar groups near the peptide backbone. We also find that branched PEGs provide superior stabilization relative to their linear counterparts, suggesting additional applications for branched PEGs in protein stabilization.

The interaction of a positively charged amino acid residue with a negatively charged residue (i.e. a salt bridge) can contribute substantially to protein conformational stability, especially when two ionic groups are in close proximity. At longer distances, this stabilizing effect tends to drop off precipitously. However, several lines of evidence suggest that salt-bridge interaction could persist at longer distances if an aromatic amino acid residue were positioned between the anion and cation. Here we explore this possibility in the context of a peptide in which a Lys residue occupies the i + 8 position relative to an i-position Glu on the solvent-exposed surface of a helix-bundle homotrimer. Variable temperature circular dichroism (CD) experiments indicate that an i + 4-position Trp enables a favorable long-range interaction between Glu and the i + 8 Lys. A substantial portion of this effect relies on the presence of a hydrogen-bond donor on the arene; however, non-polar arenes, a cyclic hydrocarbon, and an acyclic Leu side-chain can also enhance the long-range salt bridge, possibly by excluding water and ions from the space between Glu and Lys.

Background: This study examined how wide- awake local anesthesia no tourniquet (WALANT) surgery in the office versus the standard operating room (OR) impacts patient experience, and the effect wide awake virtual reality (WAVR) has in conjunction with WALANT on patient experience. Methods: This is a patient-reported outcome study of patients undergoing carpal tunnel release by a single surgeon between August 2017 and March 2021. Patients were classified by location; traditional OR versus WALANT in-office. In-office patients were further classified by whether they chose to use WAVR or not. Patients rated overall experience, enjoyability, and anxiety using a Likert scale (1–7). Results: The online survey had a 44.8% response rate. OR patients were twice as likely to report a neutral or negative experience (23% versus 11%, P = 0.03), significantly lower enjoyment scores (44% versus 20%, P = 0.0007)‚ and higher anxiety (42% versus 26%, P = 0.04) compared with office-based WALANT patients. With the addition of WAVR, office patients reported higher enjoyment than those who did not use WAVR (85% versus 73%, P = 0.05). Patients reporting an anxiety disorder were more likely to choose WAVR when compared with patients without anxiety disorder (73.8% versus 56.4%). When they chose WAVR, they had greater anxiolysis (79% versus 47%, P = 0.01)‚ and increased enjoyment (90% versus 59%, P = 0.005). Conclusions: This study demonstrates improved patient experience in the office setting, further amplified by WAVR. Preexisting anxiety disorder is a positive predictive variable toward the patients’ choice to use WAVR.