Related ArticlesDetermination of pKa values of the histidine side chains of phosphatidylinositol-specific phospholipase C from Bacillus cereus by NMR spectroscopy and site-directed mutagenesis.
Protein Sci. 1997 Sep;6(9):1937-44
Authors: Liu T, Ryan M, Dahlquist FW, Griffith OH
Two active site histidine residues have been implicated in the catalysis of phosphatidylinositol-specific phospholipase C (PI-PLC). In this report, we present the first study of the pKa values of histidines of a PI-PLC. All six histidines of Bacillus cereus PI-PLC were studied by 2D NMR spectroscopy and site-directed mutagenesis. The protein was selectively labeled with 13C epsilon 1-histidine. A series of 1H-13C HSQC NMR spectra were acquired over a pH range of 4.0-9.0. Five of the six histidines have been individually substituted with alanine to aid the resonance assignments in the NMR spectra. Overall, the remaining histidines in the mutants show little chemical shift changes in the 1H-13C HSQC spectra, indicating that the alanine substitution has no effect on the tertiary structure of the protein. H32A and H82A mutants are inactive enzymes, while H92A and H61A are fully active, and H81A retains about 15% of the wild-type activity. The active site histidines, His32 and His82, display pKa values of 7.6 and 6.9, respectively. His92 and His227 exhibit pKa values of 5.4 and 6.9. His61 and His81 do not titrate over the pH range studied. These values are consistent with the crystal structure data, which shows that His92 and His227 are on the surface of the protein, whereas His61 and His81 are buried. The pKa value of 6.9 corroborates the hypothesis of His82 acting as a general acid in the catalysis. His32 is essential to enzyme activity, but its putative role as the general base is in question due to its relatively high pKa.
Interactions of protein side chains with RNA defined with REDOR solid state NMR
Interactions of protein side chains with RNA defined with REDOR solid state NMR
Abstract Formation of the complex between human immunodeficiency virus type-1 Tat protein and the transactivation response region (TAR) RNA is vital for transcriptional elongation, yet the structure of the Tat-TAR complex remains to be established. The NMR structures of free TAR, and TAR bound to Tat-derived peptides have been obtained by solution NMR, but only a small number of intermolecular NOEs could be identified unambiguously, preventing the determination of a complete structure. Here we show that a...
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[CNS Yahoo group] Double protonated His side chains have charge +1 independent of pH
Double protonated His side chains have charge +1 independent of pH
Hi all, I am using ccpn/aria/cns combination for my structural work. I discovered a probably bad fact during the aria/cns structure calculation. In the ccpn
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01-20-2011 03:28 AM
[NMR paper] The effects of mutations on motions of side-chains in protein L studied by 2H NMR dyn
The effects of mutations on motions of side-chains in protein L studied by 2H NMR dynamics and scalar couplings.
Related Articles The effects of mutations on motions of side-chains in protein L studied by 2H NMR dynamics and scalar couplings.
J Mol Biol. 2003 Jun 6;329(3):551-63
Authors: Millet O, Mittermaier A, Baker D, Kay LE
Recently developed 2H spin relaxation experiments are applied to study the dynamics of methyl-containing side-chains in the B1 domain of protein L and in a pair of point mutants of the domain, F22L and A20V. X-ray and...
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11-24-2010 09:01 PM
[NMR paper] Unfolding kinetics of tryptophan side chains in the dimerization and hinge regions of
Unfolding kinetics of tryptophan side chains in the dimerization and hinge regions of HIV-I protease tethered dimer by real time NMR spectroscopy.
Related Articles Unfolding kinetics of tryptophan side chains in the dimerization and hinge regions of HIV-I protease tethered dimer by real time NMR spectroscopy.
Biochem Biophys Res Commun. 2000 Mar 16;269(2):387-92
Authors: Panchal SC, Hosur RV
HIV I protease has been the target of extensive and variety of investigations in recent years because of its importance in the AIDS viral life cycle. We...
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11-18-2010 09:15 PM
[NMRwiki tweet] nmrwiki: Why HCCH TOCSY does not work for whole aromatic side chains? #nmrhttp://qa.n
nmrwiki: Why HCCH TOCSY does not work for whole aromatic side chains? #nmrhttp://qa.nmrwiki.org/question/199/
nmrwiki: Why HCCH TOCSY does not work for whole aromatic side chains? #nmrhttp://qa.nmrwiki.org/question/199/
Source: NMRWiki tweets
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[NMR paper] pH-induced structural changes in human serum apotransferrin. pKa values of histidine
pH-induced structural changes in human serum apotransferrin. pKa values of histidine residues and N-terminal amino group determined by 1H-NMR spectroscopy.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www3.interscience.wiley.com-aboutus-images-wiley_interscience_pubmed_logo_FREE_120x27.gif Related Articles pH-induced structural changes in human serum apotransferrin. pKa values of histidine residues and N-terminal amino group determined by 1H-NMR spectroscopy.
Eur J Biochem. 1994 Mar 15;220(3):781-7
Authors: Kubal G, Sadler PJ, Tucker A
...
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08-22-2010 03:33 AM
[NMR paper] pH-induced structural changes in human serum apotransferrin. pKa values of histidine
pH-induced structural changes in human serum apotransferrin. pKa values of histidine residues and N-terminal amino group determined by 1H-NMR spectroscopy.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www3.interscience.wiley.com-aboutus-images-wiley_interscience_pubmed_logo_FREE_120x27.gif Related Articles pH-induced structural changes in human serum apotransferrin. pKa values of histidine residues and N-terminal amino group determined by 1H-NMR spectroscopy.
Eur J Biochem. 1994 Mar 15;220(3):781-7
Authors: Kubal G, Sadler PJ, Tucker A
...
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08-22-2010 03:33 AM
[NMR paper] Carbon-13 NMR studies of the lysine side chains of calmodulin and its proteolytic fra
Carbon-13 NMR studies of the lysine side chains of calmodulin and its proteolytic fragments.
Related Articles Carbon-13 NMR studies of the lysine side chains of calmodulin and its proteolytic fragments.
J Protein Chem. 1993 Dec;12(6):695-707
Authors: Huque ME, Vogel HJ
The pH-titration and dynamic behaviour of the seven lysine side chains in bovine calmodulin were studied by carbon-13 NMR. The amino groups of the calcium saturated protein and its proteolytic fragments TR1C (1-75) and TR2C (78-148) were dimethylated with carbon-13 labeled...
Determination of pKa values of the histidine side chains of phosphatidylinositol-spec
Linear Mode
