Enhancing the incorporation of lysine derivatives into proteins with methylester forms of unnatural amino acids

We have improved the incorporation of l- and d-forms of unnatural amino acid (UAA) N^ε-thiaprolyl-l-lysine (ThzK) into ubiquitin (UB) and green fluorescent protein (GFP) by 2–6 folds with the use of the methylester forms of the UAAs in E coli cell culture. We also improved the yields of UAA-incorporated UB and GFP with the methylester forms of N^ε-Boc-l-Lysine (BocK) and N^ε-propargyl-l-Lysine (PrK) by 2–5 folds compared to their free acid forms. Our work demonstrated that using methylester-capped UAAs for protein expression is a useful strategy to enhance the yields of UAA-incorporated proteins.     

Verbenone reduces landing of the redbay ambrosia beetle,vector of the laurel wilt pathogen,on live standing redbay trees

1. Laurel wilt is a disease that has caused extensive mortality of redbay Persea borbonia in the southeastern U.S.A. The redbay ambrosia beetle Xyleborus glabratus is the vector of the causal agent of laurel wilt, the fungus Raffaelea lauricola.
2. We tested two potential repellents to the redbay ambrosia beetle, verbenone and methyl salicylate (MeSA) in an 8‐month large‐scale experiment conducted in three locations in Florida. In each location, redbay trees were treated with a single or double application of SPLAT (Specialized Pheromone and Lure Application Technology; ISCA Technologies, Riverside, California) verbenone, as well as SPLAT with a 1:2 mix of MeSA and verbenone.
3. The MeSA + verbenone mixes did not reduce beetle captures compared with the control treatment, whereas SPLAT verbenone alone significantly reduced the number of beetles captured on sticky traps placed on redbay trees in the three locations. The reduction of beetle capture was similar regardless of one or two treatments of SPLAT verbenone. The reduction of tree death with the SPLAT verbenone treatment was not statistically significant.
4. The results of the present study suggest that trunk application of verbenone can reduce landing rates of the redbay ambrosia beetle on live redbay trees and shows promise for use in an integrated pest management strategy against laurel wilt.

     

Photophysical characterization of methyl viologen ion-exchanged within a zirconium phosphate framework

The photophysical properties of 1,1′-dimethyl-4,4′dipyridinium (methyl viologen, MV²⁺) intercalated within zirconium phosphate (ZrP) were investigated. The intercalation of MV²⁺ within ZrP was achieved by ion-exchange using a hydrated form of ZrP with six water molecules per formula unit and an interlayer distance of 10.3 Å. The intercalation yields a new phase with an interlayer distance up to 10.6 Å. The MV²⁺-exchanged ZrP material was characterized using elemental analysis, XRPD and IR data. The MV²⁺-exchanged ZrP materials show a red shift in the UV-Vis spectra in contrast with solution. The photoexcitation of nitrogen purged, MV²⁺-exchanged ZrP water suspensions with UV light leads to fluorescence emission with a maximum at 337 nm. The photoexcitation of MV²⁺-exchanged ZrP suspensions without nitrogen purging yields two fluorescence emissions with maxima at 337 and 450 nm. The emission in the visible region can be attributed to a photodecomposition product. The fluorescence quantum yields indicate that the emission of MV²⁺-exchanged ZrP is of the same order of magnitude as that of MV²⁺ in water indicating a strong deactivation of the excited state by non-radiative pathways.