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Courier
Address: |
| Phone:
(203) 785-4478
Lab:
(203) 785-2900
Fax:
(203) 785-4951
e-mail:
clifford.slayman@yale.edu |
333
Cedar Street,
SHM
B128/130
New
Haven, CT 06510 |
The
molecular machines which mediate small-molecule traffic across biological
membranes almost all either create or dissipate electric fields within
those membranes, and the resulting changes of transmembrane voltage
or current can be used not only to monitor the underlying traffic, but
also to characterize changes in the molecular structure of the
machines themselves. Micororganisms offer a vast resource for such measurements
and analysis: because of their abundance and variety, and because many
of them maintain very large transmembrane voltages—in the range of 150
to 300 mV (c.f., ~80 mV in animal cells). Such voltages are used to
drive the accumulation of nutrients, the expulsion of wastes and toxins,
and in some cases the release of useful secretory products.
Our
laboratory is presently using electrophysiological techniques as primary
assays of ion-transport processes in three different microorganisms:
Neurospora (bread mold), Candida (a facultative
human pathogen), and Saccharomyces (baker's yeast); and it
is using site-directed mutagenesis to manipulate the structures of a
variety of membrane proteins: potassium transporters (TRK & HAK
classes), proton pumps (PMA) and potassium channels (TOK).
We
are also exploring the molecular mechanisms of action of newly emerging
elements of innate immunity, viz ., so-called antimicrobial
peptides (AMPs), which serve dual roles in directly attacking invading
bacteria, fungi, and protists, and in signaling to adaptive immunity.
Many of these agents (more than a thousand are now known) also have
multiple modes of action within target microorganisms, which
makes them relatively resistant to microbial adaptation. Several classes
of these AMPs, and synthetic analogues of them, have great promise for
clinical application.
Figure caption:
Structural
model of an assembled tetramer of yeast TRK protein, SpTrk1p (from Schizosaccharomyces
). A) perspective of the membrane components
of the whole tetramer. White (background) = stick-figure
representation of six transmembrane helices in each of the four monomers.
Magenta = clustered P-loops forming the functional
K + pathways. Red & Green = clustering of the
remaining 2 x 4 transmembrane helices, to form a central pore. B,D)
Ribbon diagrams of the eight clustered helices, designated
M1d (inner) and M2d (outer), viewed
(B) down the axis of the central pore from the intracellular
surface of the yeast plasma membrane; and viewed (D)
in axial (longitudinal) section from within the plane of the membrane.
C,E) Space-filling diagrams (H atoms omitted) corresponding
to B,D . Green = neutral amino acids,
Red = basic amino acids, Blue =
acidic amino acids. Blue balls indicate the putative pathway for chloride
transit. Coordinates from H.R. Guy & S.R. Durell ( Biophys.
J. 77 : 789, 1999). Drawing by A. Rivetta ( Biophys.
J . 89 : 2412, 2005).
Selected
publications:
Click
for PDF.
Bertl,
A., Bihler, H. Kettner, C., & Slayman, C.L. , 1998.
Electrophysiology in the eukaryotic model cell, Saccharomyces
cerevisiae . Pflügers Archiv Eur. J. Physiol . 436
: 999-1013. PMID: 9799419 
Kettner,
C., Bertl, A., Obermeyer, G., Slayman, C.L., &
Bihler, H., 2003. Electrophysiological analysis of the yeast V-type
proton pump: Variable coupling ratio and proton shunt. Biophys.
J . 85 : 3730-3738. PMID:
14645064 
Kuroda,
T., Bihler, H., Bashi, E., Slayman, C.L. , & Rivetta,
A., 2004. Chloride channel function in the yeast TRK-potassium transporters.
J. Membr. Biol . 198 :177-192. PMID:
15216418 
Baev,
D., Rivetta, A., Vylkova, S., Sun, J.N., Zeng, G.-F., Slayman,
C.L. , & Edgerton, M., 2004. The TRK1 potassium transporter
is the critical effector for killing of Candida albicans by
the cationic protein, Histatin 5. J. Biol. Chem . 279
:55060-55072. PMID: 15485849 
Roller,
A., Natura, G., Bihler, H., Slayman, C.L. , Eing, C.,
& Bertl, A., 2005. In the yeast potassium channel, Tok1p, the external
ring of aspartate residues modulates both gating and conductance. Pflügers
Arch.— Europ.J.Physiol . 451 :362-370.
PMID: 16133265 
Rivetta,
A., Slayman, C.L. , & Kuroda, T., 2005. Quantitative
modeling of chloride conductance in yeast TRK potassium transporters.
Biophys. J . 89 :2412-2426.
PMID: 16040756 
Roller,
A., Natura, G., Bihler, H., Slayman, C.L., & Bertl, A., 2008. Functional
consequences of leucine and tyrosine mutations in the dual pore motifs
of the yeast K + channel, Tok1p. Pflügers Arch.— Europ.J.Physiol
. 456 ::883-896 . PMID:
18421473 
clifford.slayman@yale.edu
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