User:Andrea Foote/Sandbox 1: Difference between revisions

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PurA has also been shown to enhance expression of myelin basic protein (MBP) in developing mouse brain tissue through its binding to an MB1 regulatory motif -15 to -40 nucleotides upstream of the transcription start site. MBP is an important protein found in myelin sheaths of the central nervous system.<ref>PMID:7657701</ref>

Image:180504 PurA Repeat 1 electron density.jpg

High-affinity nucleic acid-binding function is dependent on Purα dimerization. Purα forms homodimers in addition to heterodimers with Purβ. PurA is known to repress various genes including SMαA.

<scene name='78/786627/5fgp_57and145/1'>Two aromatic residues spatially conserved on PUR repeats I and II</scene>, Y57 (repeat I) and F145 (repeat II), located on the solvent-exposed surface of the beta-sheets, contribute to the DNA unwinding activity of Purα through base stacking interactions with DNA bases.<ref>PMID:26744780</ref> <scene name='78/786627/5fgo_repeatiii/4'>PUR repeat III also has an aromatic residue at this location (Y219)</scene> that could undergo base-stacking interactions with DNA, however Weber, et al. observed negligible unwinding activity in this repeat.<ref>PMID:26744780</ref> Furthermore, this group found repeat III to bind ssDNA with significantly less (~30-fold less) affinity than repeat I-II.

<scene name='78/786627/5fgp_57and145/1'>Two aromatic residues spatially conserved on PUR repeats I and II</scene>, Y57 (repeat I) and F145 (repeat II), located on the solvent-exposed surface of the beta-sheets, contribute to the DNA unwinding activity of Purα through base stacking interactions with DNA bases.<ref>PMID:26744780</ref> Although not shown in the [[5fgp]] PDB file, Y57 interacts with a second strand of DNA via base stacking interactions with guanine. It was presumably omitted because repeat I has significantly less affinity for purine-rich DNA than does repeat II, and it is believed that most of the DNA binding and unwinding activity occurs via interactions of DNA with the beta-sheet of repeat II.<ref>PMID:26744780</ref> <scene name='78/786627/5fgo_repeatiii/4'>PUR repeat III also has an aromatic residue at this location (Y219)</scene> that could undergo base-stacking interactions with DNA, however Weber, et al. observed negligible unwinding activity in this repeat.<ref>PMID:26744780</ref> Furthermore, this group found repeat III to bind ssDNA with significantly less (~30-fold less) affinity than repeat I-II.

== Development ==

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 PurA has also been shown to enhance expression of myelin basic protein (MBP) in developing mouse brain tissue through its binding to an MB1 regulatory motif -15 to -40 nucleotides upstream of the transcription start site. MBP is an important protein found in myelin sheaths of the central nervous system.<ref>PMID:7657701</ref>
+Image:180504 PurA Repeat 1 electron density.jpg
 High-affinity nucleic acid-binding function is dependent on Purα dimerization. Purα forms homodimers in addition to heterodimers with Purβ. PurA is known to repress various genes including SMαA.
-<scene name='78/786627/5fgp_57and145/1'>Two aromatic residues spatially conserved on PUR repeats I and II</scene>, Y57 (repeat I) and F145 (repeat II), located on the solvent-exposed surface of the beta-sheets, contribute to the DNA unwinding activity of Purα through base stacking interactions with DNA bases.<ref>PMID:26744780</ref> <scene name='78/786627/5fgo_repeatiii/4'>PUR repeat III also has an aromatic residue at this location (Y219)</scene> that could undergo base-stacking interactions with DNA, however Weber, et al. observed negligible unwinding activity in this repeat.<ref>PMID:26744780</ref> Furthermore, this group found repeat III to bind ssDNA with significantly less (~30-fold less) affinity than repeat I-II.
+<scene name='78/786627/5fgp_57and145/1'>Two aromatic residues spatially conserved on PUR repeats I and II</scene>, Y57 (repeat I) and F145 (repeat II), located on the solvent-exposed surface of the beta-sheets, contribute to the DNA unwinding activity of Purα through base stacking interactions with DNA bases.<ref>PMID:26744780</ref> Although not shown in the [[5fgp]] PDB file, Y57 interacts with a second strand of DNA via base stacking interactions with guanine. It was presumably omitted because repeat I has significantly less affinity for purine-rich DNA than does repeat II, and it is believed that most of the DNA binding and unwinding activity occurs via interactions of DNA with the beta-sheet of repeat II.<ref>PMID:26744780</ref> <scene name='78/786627/5fgo_repeatiii/4'>PUR repeat III also has an aromatic residue at this location (Y219)</scene> that could undergo base-stacking interactions with DNA, however Weber, et al. observed negligible unwinding activity in this repeat.<ref>PMID:26744780</ref> Furthermore, this group found repeat III to bind ssDNA with significantly less (~30-fold less) affinity than repeat I-II.
 == Development ==