9n1b | pdb_00009n1b

Crystal structure of CysS from Corallococcus sp. CA054B with 5'-deoxyadenosine, methionine, and pantetheinylated 3-methoxyl-4-amino benzoic acid substrate bound

spinqualitylabelsall models 9n1b, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9n1b is a 1 chain structure with sequence from Corallococcus sp. CA054B. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.75Å Ligands: 5AD, A1BUN, MET, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Cystobactamids are nonribosomal peptide natural products that function as DNA gyrase inhibitors, exhibiting significant antibacterial activity. They are isolated from Cystobacter sp. Cbv34 and contain various alkoxy groups on para-aminobenzoic acid moieties, which are believed to play a crucial role in antibacterial functions. The alkoxy groups are generated by iterative methylations on a methoxy group by the cobalamin (Cbl)-dependent radical S-adenosylmethionine (SAM) enzyme CysS. CysS catalyzes up to three methylations to give ethoxy, isopropoxy, sec-butoxy, and tert-butoxy groups. For each methylation, CysS uses a ping-pong mechanism in which two molecules of SAM are consumed. One SAM is used to methylate cob(I)alamin, while another generates a 5'-deoxyadenosyl 5'-radical to initiate substrate methylation. However, little is known about how the enzyme promotes both Cbl methylation and iterative substrate methylation, which occur by polar S(N)2 and radical processes, respectively. Here, we report three X-ray crystal structures of a homolog of CysS from Corallococcus sp. CA054B. Two were determined in the presence of methoxy- and ethoxy-containing substrates, showing how CysS accommodates substrates and products during iterative methylation. The third structure, determined in the absence of a substrate, exhibits structural changes that reorient the SAM's conformation to allow for the methylation of cob(I)alamin. Structural basis for iterative methylation by a cobalamin-dependent radical S-adenosylmethionine enzyme in cystobactamids biosynthesis.,Cui J, Wang B, Maurya RK, Booker SJ Proc Natl Acad Sci U S A. 2026 Jan 27;123(4):e2527019123. doi: , 10.1073/pnas.2527019123. Epub 2026 Jan 21. PMID:41564129 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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