1i1s
From Proteopedia
(New page: 200px<br /><applet load="1i1s" size="450" color="white" frame="true" align="right" spinBox="true" caption="1i1s" /> '''SOLUTION STRUCTURE OF THE TRANSCRIPTIONAL AC...) |
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| - | [[Image:1i1s.gif|left|200px]]<br /><applet load="1i1s" size=" | + | [[Image:1i1s.gif|left|200px]]<br /><applet load="1i1s" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1i1s" /> | caption="1i1s" /> | ||
'''SOLUTION STRUCTURE OF THE TRANSCRIPTIONAL ACTIVATION DOMAIN OF THE BACTERIOPHAGE T4 PROTEIN MOTA'''<br /> | '''SOLUTION STRUCTURE OF THE TRANSCRIPTIONAL ACTIVATION DOMAIN OF THE BACTERIOPHAGE T4 PROTEIN MOTA'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Bacteriophage T4 encodes a transcription factor, MotA, that binds to the | + | Bacteriophage T4 encodes a transcription factor, MotA, that binds to the -30 region of middle-mode promoters and activates transcription by host RNA polymerase. The crystal structure of the N-terminal domain of MotA (MotNF) revealed a six-helix domain in which the two C-terminal alpha-helices mediate the formation of a dimer via a coiled-coil motif and hydrophobic interactions. This structure suggested that full-length MotA binds DNA as a dimer, but subsequent biochemical results have shown that a monomeric form of MotA binds DNA. In this study, gel filtration chromatography, dynamic light scattering, and NMR-based diffusion measurements show conclusively that MotNF is a monomer, and not a dimer, in solution. In addition, we have determined the monomeric solution structure of MotNF using NMR spectroscopy, and have compared this with the dimer structure observed in crystals. The core of the protein assumes the same helical conformation in solution and in crystals, but important differences are observed at the extreme C-terminus. In solution, helix alpha5 is followed by five disordered residues that probably link the N-terminal and C-terminal domains of MotA. In crystals, helix alpha5 forms the dimer interface and is followed by a short sixth helix that further stabilizes the dimer configuration. The solution structure of MotNF supports the conclusion that MotA functions as a monomer, and suggests that the existence of the sixth helix in crystals is a consequence of crystal packing. Our work highlights the importance of investigating protein structures in both crystals and solution to fully understand biomolecular structure and to accurately deduce relationships between structure and function. |
==About this Structure== | ==About this Structure== | ||
| - | 1I1S is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4]. Full crystallographic information is available from [http:// | + | 1I1S is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1I1S OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Bacteriophage t4]] | [[Category: Bacteriophage t4]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Kriwacki, R | + | [[Category: Kriwacki, R W.]] |
[[Category: Li, N.]] | [[Category: Li, N.]] | ||
| - | [[Category: White, S | + | [[Category: White, S W.]] |
[[Category: Zhang, W.]] | [[Category: Zhang, W.]] | ||
[[Category: coiled-coil]] | [[Category: coiled-coil]] | ||
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[[Category: transcription]] | [[Category: transcription]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:07:09 2008'' |
Revision as of 11:07, 21 February 2008
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SOLUTION STRUCTURE OF THE TRANSCRIPTIONAL ACTIVATION DOMAIN OF THE BACTERIOPHAGE T4 PROTEIN MOTA
Overview
Bacteriophage T4 encodes a transcription factor, MotA, that binds to the -30 region of middle-mode promoters and activates transcription by host RNA polymerase. The crystal structure of the N-terminal domain of MotA (MotNF) revealed a six-helix domain in which the two C-terminal alpha-helices mediate the formation of a dimer via a coiled-coil motif and hydrophobic interactions. This structure suggested that full-length MotA binds DNA as a dimer, but subsequent biochemical results have shown that a monomeric form of MotA binds DNA. In this study, gel filtration chromatography, dynamic light scattering, and NMR-based diffusion measurements show conclusively that MotNF is a monomer, and not a dimer, in solution. In addition, we have determined the monomeric solution structure of MotNF using NMR spectroscopy, and have compared this with the dimer structure observed in crystals. The core of the protein assumes the same helical conformation in solution and in crystals, but important differences are observed at the extreme C-terminus. In solution, helix alpha5 is followed by five disordered residues that probably link the N-terminal and C-terminal domains of MotA. In crystals, helix alpha5 forms the dimer interface and is followed by a short sixth helix that further stabilizes the dimer configuration. The solution structure of MotNF supports the conclusion that MotA functions as a monomer, and suggests that the existence of the sixth helix in crystals is a consequence of crystal packing. Our work highlights the importance of investigating protein structures in both crystals and solution to fully understand biomolecular structure and to accurately deduce relationships between structure and function.
About this Structure
1I1S is a Single protein structure of sequence from Bacteriophage t4. Full crystallographic information is available from OCA.
Reference
Solution structure of the transcriptional activation domain of the bacteriophage T4 protein, MotA., Li N, Zhang W, White SW, Kriwacki RW, Biochemistry. 2001 Apr 10;40(14):4293-302. PMID:11284685
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