Structural characterization of CalO1: a putative orsellinic acid methyltransferase in the calicheamicin-biosynthetic pathway

Proteins belonging to the NTF2-like superfamily are present in the biosynthetic pathways of numerous polyketide natural products, such as anthracyclins and benzoisochromanequinones. Some have been found to be bona fide polyketide cyclases, but many of them have roles that are currently unknown. Here, the X-ray crystal structures of three NTF2-like proteins of unknown function are reported: those of ActVI-ORFA from Streptomyces coelicolor A3(2) and its homologs Caci_6494, a protein from an uncharacterized biosynthetic cluster in Catenulispora acidiphila, and Aln2 from Streptomyces sp. CM020, a protein in the biosynthetic pathway of alnumycin. The presence of a solvent-accessible cavity and the conservation of the His/Asp dyad that is characteristic of many polyketide cyclases suggest a potential enzymatic role for these enzymes in polyketide biosynthesis.

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Biochemical and Structural Characterization of MycCI, a Versatile P450 Biocatalyst from the Mycinamicin Biosynthetic Pathway

ACS Chemical Biology ◽

10.1021/acschembio.6b00479 ◽

2016 ◽

Vol 11 (9) ◽

pp. 2642-2654 ◽

Cited By ~ 10

Author(s):

Matthew D. DeMars ◽

Fang Sheng ◽

Sung Ryeol Park ◽

Andrew N. Lowell ◽

Larissa M. Podust ◽

...

Keyword(s):

Structural Characterization ◽

Biosynthetic Pathway

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New ultrastructural findings about Borrelia burgdorferi by cryofixation, negative staining, thin sectioning and scanning techniques

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160467 ◽

1990 ◽

Vol 48 (3) ◽

pp. 582-583

Author(s):

S. F. Hayes ◽

M. D. Corwin ◽

T. G. Schwan ◽

D. W. Dorward ◽

W. Burgdorfer

Keyword(s):

Lyme Disease ◽

Borrelia Burgdorferi ◽

Structural Characterization ◽

Negative Staining ◽

Low Speed ◽

Thin Sectioning ◽

Ultrastructural Findings

Characterization of Borrelia burgdorferi strains by means of negative staining EM has become an integral part of many studies related to the biology of the Lyme disease organism. However, relying solely upon negative staining to compare new isolates with prototype B31 or other borreliae is often unsatisfactory. To obtain more satisfactory results, we have relied upon a correlative approach encompassing a variety EM techniques, i.e., scanning for topographical features and cryotomy, negative staining and thin sectioning to provide a more complete structural characterization of B. burgdorferi.For characterization, isolates of B. burgdorferi were cultured in BSK II media from which they were removed by low speed centrifugation. The sedimented borrelia were carefully resuspended in stabilizing buffer so as to preserve their features for scanning and negative staining. Alternatively, others were prepared for conventional thin sectioning and for cryotomy using modified procedures. For thin sectioning, the fixative described by Ito, et al.

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