Identification and Biological Activity of NFAT-133 Congeners from Streptomyces pactum

Abstract

The soil bacterium Streptomyces pactum ATCC 27456 produces a number of polyketide natural products. Among them is NFAT-133, an inhibitor of the nuclear factor of activated T cells (NFAT) that suppresses interleukin-2 (IL-2) expression and T cell proliferation. Biosynthetic gene inactivation in the ATCC 27456 strain revealed the ability of this strain to produce other polyketide compounds including analogues of NFAT-133. Consequently, seven new derivatives of NFAT-133, TM-129–TM-135, together with a known compound, panowamycin A, were isolated from the culture broth of S. pactum ATCC 27456 ΔptmTDQ. Their chemical structures were elucidated on the basis of their HRESIMS, 1D and 2D NMR spectroscopy, and ECD calculation and spectral data. NFAT-133, TM-132, TM-135, and panowamycin A showed no antibacterial activity or cytotoxicity, but weakly reduced the production of LPS-induced nitric oxide in RAW264.7 cells in a dose-dependent manner. A revised chemical structure of panowamycin A and proposed modes of formation of the new NFAT-133 analogues are also presented.

Divergent Asymmetric Synthesis of Panowamycins, TM‐135, and Veramycin F Using C−H Insertion with Donor/Donor Carbenes

“…Contemporaneous with our syntheses, Mahmud and co‐workers published their detailed work on the isolation and biological testing of panowamycin A from Streptomyces pactum ATCC 27456 [14] . In their report, they performed an updated analysis of the NMR spectra for panowamycin A, concluding that the configuration at C3 is the same that was proposed by our NMR computations.…”

Modulation of Specialized Metabolite Production in Genetically Engineered Streptomyces pactum

“…Isolation and Structure Characterization of the New Conglobatins. To identify the chemical structures of new conglobatin analogues, the EtOAc extract of the culture broth was subjected to successive isolation procedures using reversephase HPLC to give four new conglobatins, namely, conglobatin B2 (15), B3 (16), F1 (17), and F2 (18) (Figure 4)on the basis of their chemical structuresalong with a known conglobatin analogue, conglobatin B1 (8). 28 Conglobatin B2 (15) was isolated as a yellow oil with a postulated molecular formula of C 27 H 36 N 2 O 6 (HRESIMS m/z 485.2646 [M + H] + ), which is one carbon and two hydrogen atoms fewer than conglobatin.…”

“…The third compound, conglobatin F1 (17), was also isolated as a yellow oil with a suggested molecular formula of C 29 H 40 N 2 O 6 (m/z 513.2961 [M + H] + ). In contrast to conglobatin B2 and conglobatin B3, conglobatin F1 contains one carbon and two hydrogen atoms more than 1.…”

“… In silico analysis of the genome sequence uncovered 31 putative BGCs, among which nine are polyketide synthase (PKS) gene clusters, including ptmQ , which encodes an iterative type-I PKS responsible for the production of 6-methylsalicylate in pactamycin biosynthesis. ,− In addition to pactamycin, the ATCC 27456 strain also produces the polyketides NFAT-133 ( 2 ), piericidins ( 3 – 6 ), and conglobatin ( 7 ) (Figure ). ,, The aromatic polyketide NFAT-133, which is the major product of this strain, has immunosuppressive, antidiabetic, and antitrypanosomal activities. It inhibits the nuclear factor of activated T cells (NFAT), which is responsible for its immunosuppressive activity, and activates the AMPK pathway, which causes the increase of insulin-stimulated glucose uptake in L6 myotubes.…”

“…10,13−15 In addition to pactamycin, the ATCC 27456 strain also produces the polyketides NFAT-133 (2), piericidins (3−6), and conglobatin (7) (Figure 1). 11,16,17 The aromatic polyketide NFAT-133, which is the major product of this strain, has immunosuppressive, antidiabetic, and antitrypanosomal activities. It inhibits the nuclear factor of activated T cells (NFAT), which is responsible for its immunosuppressive activity, and activates the AMPK pathway, which causes the increase of insulin-stimulated glucose uptake in L6 myotubes.…”