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Background: Dihydromethanopterin reductase catalyzes the final step of methanopterin biosynthesis. Results: The crystal structure is a 24-subunit cubic protein cage with 48 molecules of bound FMN. Conclusion: Analyses indicate a reaction mechanism in which distinct FMNs act as cofactor and electron donor. Significance: The structures illuminate a new mechanism for pterin reduction and reveal an extraordinarily elaborate assembly for electron transfer in the cell.

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Solid-liquid equilibria for three organic binary mixtures of hexanedioic acid (1) + benzoic acid (2) (eutectic temperature T E ) 378.17 K, eutectic composition x 1E ) 0.249), benzoic acid (1) + pentanedioic acid (2) (T E ) 343.50 K, x 1E ) 0.402), and hexanedioic acid (1) + pentanedioic acid (2) (T E ) 355.87 K, x 1E ) 0.205) were measured using differential scanning calorimetry (DSC). Simple eutectic behaviors for these systems were observed. The experimental results were correlated using the Wilson and nonrandom twoliquid (NRTL) activity coefficient models with satisfactory results.

Solid polymer electrolytes (SPEs) are suitable materials for safety enhancements of high-energy-density lithium metal batteries. Low ionic conductivity and poor interfacial compatibility could be the major issues to be addressed for SPEs. In this work, a cross-linked polybenzoxazine polymer with poly(ethylene oxide) (PEO) segments (CR-PEO-PBz) has been synthesized and used as a polymeric matrix for preparation of SPEs. The cross-linked structure contributes to suppression of PEO crystallization. PEO-PBz is also used as a binder to reduce the interfacial resistance between the electrode and the electrolyte. The features enhance the lithium ion transportation and increase the ionic conductivity of the corresponding SPE (5.32 × 10 −1 mS cm −1 at 60 °C). CR-PEG-PBz also exhibits the ability to prevent lithium dendrite growth with promotion of uniform lithium deposition. The LiFePO 4 /Li coin cells made with the SPEs demonstrate a high initial capacity of 142 mAh g −1 at 0.2C and 60 °C and a 93% initial capacity after a 100-cycle test. The cells could be operated at 30, 40, and 50 °C, thus proving the capability of the SPE at various temperatures.