Spectral analysis of radical metalloenzyme using EPR in Hydrolases

One of the categories of hydrolase is acid phosphatase which is isolated from sweet potato (spAP). It contains metal ions such as Zn, Mn, Fe etc. with molecular weight 110kDa. An aqueous epr spectrum in buffer (pH 5.6) exhibits class II mixed valence nature of Fe+3 together with Fe+2, Mn+2, Zn+2 and Cu+2 metallobiosites. It indicates reduced form of enzyme with gMn(II)= 2.0084 and grad= 2.0041 signals with radical signal. The localized electron interaction with 55Mn+2 nucleus is evidenced by six-hyperfine splitted spin allowed transitions flanked by ten satellite lines. Allowed and forbidden doublets are computed with A (55Mn) coupling constant~96 G and Zfs parameter D=0.029 cm-1. The spin integration of Tyrradical signal is shown in lyophilized sample spectrum (1.029 x 1015 spins /gm). It also shows DNA cleavage activity with pUC 19 plasmid DNA.

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DNA-cleavage activity of the iron(II) complex with optically active ligands, meta- and para-xylyl-linked N’,N’-dipyridylmethyl-cyclohexane-1,2-diamine

Bioorganic & Medicinal Chemistry Letters ◽

10.1016/j.bmcl.2021.127834 ◽

2021 ◽

Vol 36 ◽

pp. 127834

Author(s):

Koichi Kato ◽

Yoshimi Ichimaru ◽

Yoshinori Okuno ◽

Yoshihiro Yamaguchi ◽

Wanchun Jin ◽

...

Keyword(s):

Dna Cleavage ◽

Optically Active ◽

Cleavage Activity ◽

Dna Cleavage Activity

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A YoeB toxin cleaves both RNA and DNA

Scientific Reports ◽

10.1038/s41598-021-82950-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Julia McGillick ◽

Jessica R. Ames ◽

Tamiko Murphy ◽

Christina R. Bourne

Keyword(s):

Dna Cleavage ◽

Divalent Cations ◽

Nuclease Activity ◽

Dose Dependence ◽

Cleavage Activity ◽

Double Stranded Dna ◽

Dna Cleavage Activity ◽

Evolutionarily Conserved ◽

Toxin Protein ◽

Rna And Dna

AbstractType II toxin-antitoxin systems contain a toxin protein, which mediates diverse interactions within the bacterial cell when it is not bound by its cognate antitoxin protein. These toxins provide a rich source of evolutionarily-conserved tertiary folds that mediate diverse catalytic reactions. These properties make toxins of interest in biotechnology applications, and studies of the catalytic mechanisms continue to provide surprises. In the current work, our studies on a YoeB family toxin from Agrobacterium tumefaciens have revealed a conserved ribosome-independent non-specific nuclease activity. We have quantified the RNA and DNA cleavage activity, revealing they have essentially equivalent dose-dependence while differing in requirements for divalent cations and pH sensitivity. The DNA cleavage activity is as a nickase for any topology of double-stranded DNA, as well as cleaving single-stranded DNA. AtYoeB is able to bind to double-stranded DNA with mid-micromolar affinity. Comparison of the ribosome-dependent and -independent reactions demonstrates an approximate tenfold efficiency imparted by the ribosome. This demonstrates YoeB toxins can act as non-specific nucleases, cleaving both RNA and DNA, in the absence of being bound within the ribosome.

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