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The C Users' Group Library 1994 August
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wc-cdrom-cusersgrouplibrary-1994-08.iso
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vol_200
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211_01
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xsrch.tst
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.ig XSRCH.TST VERS:- 01.00 DATE:- 09/26/86 TIME:- 09:37:59 PM
.. Test file consisting of several CAS abstracts for use in trials of xsrchr
.. (CAS abstracts are the default option if XSRCH.ZIP = XSRCHCAS.ZIP):
..
.. Usage: xsrchr xsrch.tst +results_file
.. [the program then enters full screen input -
.. it is setup for condensing CAS files -
.. enter ESC to continue]
..
.. XSRCHR extracts condensed files like XMERGE1.TST, etc, from
.. full abstract files.
.. XSRCHR also can extract records satisfying specific search strings.
*
ANSWER 1 OF 5
AN CA103(25):209170v
TI Hydrogen-bonding networks in bacteriorhodopsin may afford a proton
pathway and structural stability
AU Rosenbusch, J. P.
CS Eur. Mol. Biol. Lab.
LO Heidelberg 6900, Fed. Rep. Ger.
SO Bull. Inst. Pasteur (Paris), 83(3), 207-20
SC 6-3 (General Biochemistry)
DT J
CO BIPAA8
IS 0020-2452
PY 1985
LA Eng
AB A structure of bacteriorhodopsin is proposed that may explain
functional and structural properties which have not been previously
accounted for. Its pattern is derived uniquely from the
identification of turn regions as shown by C. Paul and J. P.
Rosenbusch (1985). Significantly more polar and potentially ionized
groups would be contained in the hydrophobic domain of the membrane
than previously assumed, and would form extensive networks of H
bonds. Criteria for residues which may contribute to proton
conduction, combined with topol. considerations, suggest specific
linear proton pathways that span the entire membrane in discrete
steps. Two examples are presented, both of which comprise carboxyl
and tyrosyl residues as pa⌠h≈ay π∩nstituents and include the
retinal-linked lysine. The proximities of the groups involved as
well as the very short helix-linking segments impose stringent topol.
criteria. This allows probing of whether the proposed dense
H-bonding systems could afford satn. of all donor and acceptor
groups. Irresp. of detailed assignments, such satn. appears
possible. H bonds within and between helixes could explain the
unusual stability of bacteriorhodopsin and could also account for
interactions between monomers, allowing their assocn. to purple
membranes. Although this working hypothesis appears to offer
plausible interpretations for several crit. properties of
bacteriorhodopsin, it is likely to be as resistant to unequivocal
proof as previously proposed models. Before the structure is known
at at. resoln., however, the notion of extensive H bonding within
hydrophobic domains in the protein and membrane interior may
nonetheless refresh the concepts of the principles governing membrane
protein structure.
KW bacteriorhodopsin structure model function; hydrogen bond network
bacteriorhodopsin; membrane protein hydrogen bond network
IT Halobacterium halobium
(bacteriorhodopsin of, hydrogen-bond network in, protein structure
and function in relation to)
IT Bacteriorhodopsins
(hydrogen bond network in, hydrogen ion transport and monomer
assocn. in relation to)
IT Proteins
(membranes, hydrogen-bond network in, structure and function at)
IT Hydrogen bond
(network, in bacteriorhodopsin, hydrogen ion transport and monomer
assocn. in relation to)
IT Conformation and Conformers
Molecular structure, natural product
(of bacteriorhodopsin, hydrogen-bond network in, membrane protein
structure and function in relation to)
IT Biological transport
(of hydrogen ions, by bacteriorhodopsin, hydrogen-bond network in,
membrane protein structure and function in relation to)
IT 12408-02-5, biological studies
(transport of, by bacteriorhodopsin, hydrogen-bond network in
relation to)
*
ANSWER 2 OF 5
AN CA102(5):41618a
TI On the role of hydrogen bonds and hydrogen-bonded systems with large
proton polarizability for mechanisms of proton activation and
conduction in bacteriorhodopsin
AU Zundel, G.; Merz, H.
CS Inst. Phys. Chem., Univ. Munich
LO Munich D-8000/2, Fed. Rep. Ger.
SO Prog. Clin. Biol. Res., 164(Inf. Energy Transduction Biol. Membr.),
153-64
SC 6-0 (General Biochemistry)
SX 10
DT J
CO PCBRD2
IS 0361-7742
PY 1984
LA Eng
AB A review with 45 refs. H bonds and H-bonded chains with large proton
polarizability are of decisive importance, both for the activation of
protons and the conduction of the pos. charge in bacteriorhodopsin.
KW review bacteriorhodopsin proton transfer hydrogen; hydrogen bond
bacteriorhodopsin pump review
IT Hydrogen bond
(in proton transport by bacteriorhodopsin)
IT Bacteriorhodopsins
(proton transport in, hydrogen bonds and hydrogen-bonded systems
in)
IT 12408-02-5, biological studies
(transport of, in bacteriorhodopsin, hydrogen bonds and
hydrogen-bonded systems in)
*
ANSWER 3 OF 5
AN CA97(23):194653m
TI Light-induced aldimine bond migration as a possible mechanism for
proton transfer in bacteriorhodopsin
AU Ovchinnikov, Yu. A.; Abdulaev, N. G.
CS Shemyakin Inst. Bioorg. Chem.
LO Moscow 117988, USSR
SO Membr. Transp., Volume 2, 319-22. Edited by: Martonosi, Anthony N.
Plenum: New York, N. Y.
SC 6-1 (General Biochemistry)
DT C
CO 48ETAH
PY 1982
LA Eng
AB The light-driven proton-transporting mechanism of bacteriorhodopsin
(BR) in membranes appears to involve proton-specific channels formed
by chains of H bonds within the mol. This mechanism is supported by
exptl. studies on aldimine bond migration occurring during the BR
photocycle in which retinal covalently attached to the .epsilon.-NH2
group of lysine-41 (Lys-41) in the dark migrates to Lys-215 on
illumination. The protonation and deprotonation of retinal aldimines
in different microenvironments of BR is advantageous for proton
transport across the purple membrane.
KW bacteriorhodopsin photocycle aldimine proton transport
IT Light, biological effects
(aldimine bond migration in bacteriorhodopsin induced by, hydrogen
ion transport in relation to)
IT Bacteriorhodopsins
(aldimine bond migration in photocycle of, hydrogen ion transport
in relation to)
IT Hydrogen bond
(of bacteriorhodopsin, photocycle effect on, hydrogen ion
transport in relation to)
IT Biological transport
(of hydrogen ion, by purple membrane in bacteriorhodopsin
photocycle, aldimine bond migration in relation to)
IT Cell membrane
(purple, bacteriorhodopsin hydrogen bonding in, photocycle effect
on)
IT 116-31-4
(migration of, in bacteriorhodopsin photocycle, hydrogen ion
transport in relation to)
IT 12408-02-5, biological studies
(transport of, by purple membrane in bacteriorhodopsin photocycle,
aldimine bond migration in relation to)
*
ANSWER 4 OF 5
AN CA95(19):164133h
TI Proton conduction in bacteriorhodopsin via a hydrogen-bonded chain
with large proton polarizability
AU Merz, Helmut; Zundel, Georg
CS Phys.-Chem. Inst., Univ. Muenchen
LO Munich D-8000/2, Fed. Rep. Ger.
SO Biochem. Biophys. Res. Commun., 101(2), 540-6
SC 6-3 (General Biochemistry)
DT J
CO BBRCA9
IS 0006-291X
PY 1981
LA Eng
AB A Corey-Pauling-Kolthun mol. model of bacteriorhodopsin was built.
This model shows that a largely structurally sym. H-bonded chain
Asp-Tyr-Tyr-Tyr-Tyr-Tyr-Tyr-Glu may be formed. With regard to the
total proton potential this chain shows very large proton
polarizability and thus via this chain the pos. charge can be
conducted to the outside of the membrane via a Grotthus mechanism.
KW bacteriorhodopsin proton transport hydrogen bond
IT Bacteriorhodopsins
(hydrogen ion transport by, hydrogen-bonded peptide chain in
relation to)
IT Hydrogen bond
(of peptide chain, of bacteriorhodopsin, hydrogen ion transport in
relation to)
IT 12408-02-5, biological studies
(transport of, in bacteriorhodopsin, hydrogen-bonded peptide chain
in relation to)
*
ANSWER 5 OF 5
AN CA94(15):116126r
TI Molecular models of proton pumps
AU Nagle, J. F.; Mille, M.
CS Dep. Phys., Carnegie-Mellon Univ.
LO Pittsburgh, PA 15213, USA
SO J. Chem. Phys., 74(2), 1367-72
SC 6-1 (General Biochemistry)
DT J
CO JCPSA6
IS 0021-9606
PY 1981
LA Eng
AB Three theor. models of proton pumps are discussed at the mol. level.
The models contain H bonded chains, which are the best understood
channels, structurally and kinetically, for proton conduction within
membranes. The 1st model, called the integral injector model, has an
active site which involves a pK change. The 2nd model, called the
switch model, utilizes a conformational change in a retinal as the
active site. The 3rd model, called the active chain model, involves
a conformational change in the protein, and the active site is
delocalized to include the entire H-bonded chain. The models
presented were chosen in part because of their possible relevance to
the bacteriorhodopsin proton pump and are compared with this system,
but the basic principles involved have greater generality. They were
chosen to explore the general family of theor. proton pumps. Each
model illustrates general principles that form a basis for generating
addnl. models in the family.
KW proton pump membrane model; bacteriorhodopsin proton pump model
IT Chains, chemical
(conformational transitions of, of proton pump protein,
mechanistic model in relation to)
IT Hydrogen bond
(in proton pump models)
IT Biological transport
(of hydrogen ion, mechanism of, model of)
IT Conformational inversion
(of retinal, proton pump mechanism in relation to)
IT Bacteriorhodopsins
(proton transport by, mechanism of, models of)
IT Membranes and Diaphragms
(biol., proton transport by, mechanism of, models of)
IT 12408-02-5, biological studies
(transport of, model of)