Pyrroloquinoline quinone (PQQ) has received considerable attention due to its numerous important physiological functions. PqqA is a precursor peptide of PQQ with two conserved residues: glutamate and tyrosine. After linkage of the C␥ of glutamate and C⑀ of tyrosine by PqqE, these two residues are hypothesized to be cleaved from PqqA by PqqF. The linked glutamate and tyrosine residues are then used to synthesize PQQ. Here, we demonstrated that the pqqF gene is essential for PQQ biosynthesis as deletion of it eliminated the inhibition of prodigiosin production by glucose. We further determined the crystal structure of PqqF, which has a closed clamshell-like shape. The PqqF consists of two halves composed of an N-and a C-terminal lobe. The PqqF-N and PqqF-C lobes form a chamber with the volume of the cavity of ϳ9400 Å 3 . The PqqF structure conforms to the general structure of inverzincins. Compared with the most thoroughly characterized inverzincin insulin-degrading enzyme, the size of PqqF chamber is markedly smaller, which may define the specificity for its substrate PqqA. Furthermore, the 14-amino acid-residue-long tag formed by the N-terminal tag from expression vector precisely protrudes into the counterpart active site; this N-terminal tag occupies the active site and stabilizes the closed, inactive conformation. His-48, His-52, Glu-129 and His-14 from the N-terminal tag coordinate with the zinc ion. Glu-51 acts as a base catalyst. The observed histidine residue-mediated inhibition may be applicable for the design of a peptide for the inhibition of M16 metalloproteases.Pyrroloquinoline quinone (PQQ), 4 an aromatic orthoquinone, has been recognized as the third class of redox cofactors in addition to the well known cofactors, nicotinamide (NAD(P) ϩ ) and flavin (FAD, FMN) (1). PQQ was first identified from methanol dehydrogenase in methylotrophic bacteria (2), and several bacterial dehydrogenases, such as glucose dehydrogenases, quinate dehydrogenase, and alcohol dehydrogenase, were later found to be quinoproteins (3-5). Recently, sugar oxidoreductase in the basidiomycete Coprinopsis cinerea (6), 2-keto-D-glucose dehydrogenase from Pseudomonas aureofaciens (7) and pyranose dehydrogenase from C. cinerea (8) were all characterized as novel PQQ-dependent enzymes. Free PQQ has been identified in a wide variety of foods (9) and milk (10). PQQ is an essential nutrient for proper growth and development in mice (11). The strong-antioxidant capacity of PQQ protects living cells and biomolecules from oxidative stress in vivo and in vitro (12, 13). Furthermore, PQQ exerts a protective effect against ultraviolet irradiation-induced human dermal fibroblast senescence in vitro (14) and suppresses the serum low density cholesterol level to prevent various diseases (15). In addition, PQQ may improve skin conditions and slow the progression of osteoarthritis (16).The chemical structure of PQQ was determined in 1980 (17). Since then gene clusters involved in the synthesis of PQQ from different bacteria that range from 4 genes ...

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Violacein, a natural purple secondary metabolite, is sequentially biosynthesized by five enzymes in the following pathway: VioA-VioB-VioE-VioD-VioC. VioD, a flavin-dependent oxygenase, catalyzes the hydroxylation of the intermediate product prodeoxyviolaceinic acid (PVA) at the 5-position of one indole ring to yield proviolacein. In vitro biochemical data have revealed this process, but the catalytic mechanism still remains largely unclear. Here, the cloning, expression, purification, crystallization and diffraction of VioD are reported. Crystals of VioD diffracted to 1.7 Å resolution and belonged to space group P31, with unit-cell parameters a = b = 90.0, c = 94.5 Å, α = β = 90, γ = 120°. Solvent-content calculation and molecular-replacement results suggest the presence of two molecules of VioD in the asymmetric unit.

Background: Anti-CD19 chimeric antigen receptor T cell therapies (CAR-T) have shown impressive clinical outcomes in relapsed/refractory (R/R) CD19+ B-cell non-Hodgkin lymphomas (B-NHL) and acute lymphoblastic leukemias (B-ALL). However, 30%-60% of patients with B-ALL who initially responded to anti-CD19 CAR-T therapies relapsed either due to poor CAR-T persistence or CD19 antigen escape, and preliminary data also indicated CD19 antigen loss in patients with B-NHL relapsed after anti-CD19 CAR-T therapy. In addition, the immunogenicity of murine origin CAR construct is another cause of limited in vivo CAR-T persistence. Design: To overcome these problems, a novel fully human anti-CD19×anti-CD22 dual targeted CAR-T cell product - CT120, has been developed. The CT120 CAR molecule contains tandem fusion of anti-CD19 and anti-CD22 scFv, which can effectively recognize CD19 and CD22 antigen independently, to avoid antigen escape. The intracellular CAR domain contains CD3ζ and 4-1BB co-stimulatory domain, which can improve in vivo persistence. In addition, both anti-CD19 and anti-CD22 antibody were generated from proprietary fully human libraries to minimize possible immunogenicity. The CAR molecule was transferred to autologous T cells through a lentiviral backbone. Results: The anti-CD19 and anti-CD22 scFv binds to its antigen in nanomolar range, and CT120 CAR-T cells can bind to both CD19 and CD22 antigens in a noncompetitive manner. CT120 CAR-T cells showed potent in vitro cytotoxicity not only to target B-cell lymphoma/leukemia cell lines (Raji, Daudi, and NALM-6), but also to the CD19 knockout (CD19-CD22+) and CD22 knockout (CD19+CD22-) Raji cell lines. CT120 can secret multiple cytokines, such as IL-2, TNF-α and IFN-γ, and proliferate efficiently after engagement of target cells. In vivo efficacy study demonstrated that CT120 CAR-T cells expanded effectively in mice and completely inhibit Raji and NALM-6 tumor cell growth. Furthermore, CT120 showed a favorable safety profile and promising efficacy in patients with r/r B-NHL and B-ALL in an investigator-initiated trial (IIT). Certain patients who relapsed after previous murine origin CAR-T treatment also benefited from CT120 therapy. Conclusion: Collectively, CT120 is a potent and safe anti-CD19×anti-CD22 dual target CAR-T product for the treatment of B-NHL and B-ALL, and now it is in registered phase 1/2 clinical trial. Citation Format: Panpan Niu, Qianli Hu, Jialu Mo, Guangrong Meng, Xiangyin Jia, Wei Cheng, Qiaoe Wei, Zhenyu Dai, Xuefeng Wu, Guang Hu, Taochao Tan, Jianfeng Zhou, Yongkun Yang, gang Hu. CT120, a novel fully human anti-CD19 x anti-CD22 dual targeted chimeric antigen receptor T cell product for the treatment of B-NHL and B-ALL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2811.