4 research outputs found
Miniaturized bioaffinity assessment coupled to mass spectrometry for guided purification of bioactives from toad and cone snail
No full textA nano-flow high-resolution screening platform, featuring a parallel chip-based microfluidic bioassay and mass spectrometry coupled to nano-liquid chromatography, was applied to screen animal venoms for nicotinic acetylcholine receptor like (nAChR) affinity by using the acetylcholine binding protein, a mimic of the nAChR. The potential of this microfluidic platform is demonstrated by profiling the Conus textile venom proteome, consisting of over 1, 000 peptides. Within one analysis
Interconverting Conformations of Slipped-DNA Junctions Formed by Trinucleotide Repeats Affect Repair Outcome
No full textExpansions of (CTG)·(CAG) repeated DNAs are the
mutagenic
cause of 14 neurological diseases, likely arising through the formation
and processing of slipped-strand DNAs. These transient intermediates
of repeat length mutations are formed by out-of-register mispairing
of repeat units on complementary strands. The three-way slipped-DNA
junction, at which the excess repeats slip out from the duplex, is
a poorly understood feature common to these mutagenic intermediates.
Here, we reveal that slipped junctions can assume a surprising number
of interconverting conformations where the strand opposite the slip-out
either is fully base paired or has one or two unpaired nucleotides.
These unpaired nucleotides can also arise opposite either of the nonslipped
junction arms. Junction conformation can affect binding by various
structure-specific DNA repair proteins and can also alter correct
nick-directed repair levels. Junctions that have the potential to
contain unpaired nucleotides are repaired with a significantly higher
efficiency than constrained fully paired junctions. Surprisingly,
certain junction conformations are aberrantly repaired to expansion
mutations: misdirection of repair to the non-nicked strand opposite
the slip-out leads to integration of the excess slipped-out repeats
rather than their excision. Thus, slipped-junction structure can determine
whether repair attempts lead to correction or expansion mutations
