- Email: [email protected]
Solution NMR of water on protein surfaces
“Of particular interest” in the opinion of structural biologists. Papers “of particular interest” selected, from the previous year’s literature, by the authors of reviews in the section on Biophysical Methods in the December 1992 issue of Current Opinion in Structural Biology.
Initial electron-transfer photosynthetic bacteria
events in
TEM~LER RH: Measurements
selected by Theodore J. DiMagno, Zhiyu VVang and James R. Norris KIRMAIER C, HOLTEN D: An Assessment of the Mechanism of Initial Electron Transfer in Bacterial Reaction Centers. Biocbemishy 1991, 30:609-613. This paper shows convincingly that unequivocal proof for the two-step sequential mechanism is not available. Such proof rests on the unambiguous identification of discrete intermediate species, such as the anion of the accessory bacteriochlorophyll on the active M branch. Non-exponential behavior and sample heterogeneity are also discussed. M, JORTNER J, MICHEL-BEYERLE ME: On the Mechanism of the Primary Charge Separation in Bacterial Photosynthesis. Biocbim Biopbys Actu 1991, 1056:301-315. This paper provides a lucid and very important theoretical discussion of the one-step superexchange mechanism versus the two-step sequential mechanism. In addition, the theoretical discussion is closely connected with well known experimentall results. BIXON
Vos MII, LAMBRY JC, ROBLES SJ, YOUVAN DC, BRETON J, MARTINJ-L: Direct Observation of Vibrational Coherence in Bacterial Reaction Centers Using Femtosecond Absorption Spectroscopy. Proc Natl Acad Sci USA 1991, EEW385-8889. This experimental work is the first to observe oscillatory behavior in the stimulated emission decay of the first excited singlet state OFthe special pair. Oscillatory behavior is not observed during the formation of products.
Developments
im X-ray detectors
selected
by
James W. Pflugrath SAKABE N: X-ray IDiffraction Data Collection System for Modern Protein Crystallography with a Weissenberg Camera and an Imaging Plate Using Synchrotron Radiation. Nucl Instr Meth Pbys Res [AJ 1991, 303:448-463. This paper describes in some detail the set up and operation of the imaging plate system at station BLGAZ in the Photon Factory, Tsukuba, Japan. The performance and further developments of this very highly regarded system are well documented.
664
on Some Characteristics of BaF’Br:Euz+ Relevant to Its Use as a Storage Phosphor for X-ray DiITraction Imaging. NucZ Znstr Metb Pbys Res [A/ 1991, 300:357-366. The signal storage stability, signal zeroing and absolute signal sensitivity of the BaFBr:Euz+ phosphor used in imaging plates are measured. Changes in the construction of the image plates to improve their erasure, spatial resolution, dynamic range and signal storage stability are suggested.
Solution
NMR of water on protein
selected by Mark G. Kubinec Wemmer
surfaces
and David
E.
G, LIEPINSH E, WUTHFXCH K: Proton Exchange with Internal Water Molecules in the Protein BIT1 in Aqueous Solution. J Am Chem Sot 1991, 113:4363-4364. This paper represents the last word (so far) on the elusive upper limit for the exchange lifetime of internal water molecules. A value of N 1 ms is established using shift reagents to modify the water chemical shit. O’ITING
O’ITING G, LIEPINSH E, W~HRICH
K: Protein Hydration in Aqueous Solution. Science 1991, 254974980. This paper provides a comparison of the hydration patterns of a folded protein and a peptide in which all residues are exposed to solvent. Surface hydration is discussed and a distinction is made between internal and surface water. Protein-water interaction data are rationalized using a model mat includes dill&ion of water into and out of sites on the surface of the protein. The model is intuitively pleasing, and the analysis allows the more complete assignment of exchange rates to various hydration water molecules. CLORE GM, GRONENBORN AM: Localization of Bound Water in the Solution Structure of the Immunoglobulin Binding Domain of Streptococcal Protein-G, Evidence for Solvent-Induced Helical Distortion ii* Solution. J Mol Biol 1992, 223~53-856. It is demonstrated that surface hydration water can exist in the longer lifetime regime of internal water molecules (greater than 1 ns). The authors speculate ‘that the stability of the bound water stems from bifurcating hydrogen bonding involving NH and CO backbone moieties These strongly bound waters may also stabilize elemen. of tertiary structure in the protein.
@ 1992 Current Biology
Initial electron-transfer photosynthetic bacteria
events in
TEM~LER RH: Measurements
selected by Theodore J. DiMagno, Zhiyu VVang and James R. Norris KIRMAIER C, HOLTEN D: An Assessment of the Mechanism of Initial Electron Transfer in Bacterial Reaction Centers. Biocbemishy 1991, 30:609-613. This paper shows convincingly that unequivocal proof for the two-step sequential mechanism is not available. Such proof rests on the unambiguous identification of discrete intermediate species, such as the anion of the accessory bacteriochlorophyll on the active M branch. Non-exponential behavior and sample heterogeneity are also discussed. M, JORTNER J, MICHEL-BEYERLE ME: On the Mechanism of the Primary Charge Separation in Bacterial Photosynthesis. Biocbim Biopbys Actu 1991, 1056:301-315. This paper provides a lucid and very important theoretical discussion of the one-step superexchange mechanism versus the two-step sequential mechanism. In addition, the theoretical discussion is closely connected with well known experimentall results. BIXON
Vos MII, LAMBRY JC, ROBLES SJ, YOUVAN DC, BRETON J, MARTINJ-L: Direct Observation of Vibrational Coherence in Bacterial Reaction Centers Using Femtosecond Absorption Spectroscopy. Proc Natl Acad Sci USA 1991, EEW385-8889. This experimental work is the first to observe oscillatory behavior in the stimulated emission decay of the first excited singlet state OFthe special pair. Oscillatory behavior is not observed during the formation of products.
Developments
im X-ray detectors
selected
by
James W. Pflugrath SAKABE N: X-ray IDiffraction Data Collection System for Modern Protein Crystallography with a Weissenberg Camera and an Imaging Plate Using Synchrotron Radiation. Nucl Instr Meth Pbys Res [AJ 1991, 303:448-463. This paper describes in some detail the set up and operation of the imaging plate system at station BLGAZ in the Photon Factory, Tsukuba, Japan. The performance and further developments of this very highly regarded system are well documented.
664
on Some Characteristics of BaF’Br:Euz+ Relevant to Its Use as a Storage Phosphor for X-ray DiITraction Imaging. NucZ Znstr Metb Pbys Res [A/ 1991, 300:357-366. The signal storage stability, signal zeroing and absolute signal sensitivity of the BaFBr:Euz+ phosphor used in imaging plates are measured. Changes in the construction of the image plates to improve their erasure, spatial resolution, dynamic range and signal storage stability are suggested.
Solution
NMR of water on protein
selected by Mark G. Kubinec Wemmer
surfaces
and David
E.
G, LIEPINSH E, WUTHFXCH K: Proton Exchange with Internal Water Molecules in the Protein BIT1 in Aqueous Solution. J Am Chem Sot 1991, 113:4363-4364. This paper represents the last word (so far) on the elusive upper limit for the exchange lifetime of internal water molecules. A value of N 1 ms is established using shift reagents to modify the water chemical shit. O’ITING
O’ITING G, LIEPINSH E, W~HRICH
K: Protein Hydration in Aqueous Solution. Science 1991, 254974980. This paper provides a comparison of the hydration patterns of a folded protein and a peptide in which all residues are exposed to solvent. Surface hydration is discussed and a distinction is made between internal and surface water. Protein-water interaction data are rationalized using a model mat includes dill&ion of water into and out of sites on the surface of the protein. The model is intuitively pleasing, and the analysis allows the more complete assignment of exchange rates to various hydration water molecules. CLORE GM, GRONENBORN AM: Localization of Bound Water in the Solution Structure of the Immunoglobulin Binding Domain of Streptococcal Protein-G, Evidence for Solvent-Induced Helical Distortion ii* Solution. J Mol Biol 1992, 223~53-856. It is demonstrated that surface hydration water can exist in the longer lifetime regime of internal water molecules (greater than 1 ns). The authors speculate ‘that the stability of the bound water stems from bifurcating hydrogen bonding involving NH and CO backbone moieties These strongly bound waters may also stabilize elemen. of tertiary structure in the protein.
@ 1992 Current Biology