CONFORMATIONAL CHANGES AT THE NUCLEOTIDE-BINDING SITE OF
KINESIN-FAMILY MOTORS ED PATE WSU FORCE GENERATION IN MUSCLE IS
PRODUCED BY THE INTERACTION OF TWO PROTEINS: ACTIN AND MYOSIN
MYOSIN ACTIN MYOSIN KINESIN NUCLEOTIDE BINDING SITE MYOSINKINESIN
NCDMYOSIN COMPARISON OF NCD AND MYOSIN BINDING SITES LOCATION
OFKINESIN CYS-188 VANT HOFF ANALYSIS SHOWS H 0 = -100 KJ/MOL FOR
THE TRANSITION ANALOG ANGLE EPR ncd SSL-NANDP44 SL-NANDP>28
2'-SLADP12 3'-SLADP>12 2', 3'-SLADP>16 kinesin SSL-NANDP35
SL-NANDP32 2'-SLADP>10 3'-SLADP11 2', 3'-SLADP>18 SUMMARY OF
CONE ANGLE CHANGES ON BINDING TO MICROTUBULES CONSTRUCTION OF NCD
WITH SWITCH 1 CLOSED ADP P-LOOP SWITCH 2 NCD SWITCH 1 CONSTRUCTION
OF NCD WITH SWITCH 1 CLOSED P-LOOP SWITCH 2 NCD SWITCH 1 MYOSIN
SWITCH 1 CONSTRUCTION OF NCD WITH SWITCH 1 CLOSED ADP P-LOOP SWITCH
2 NCD SWITCH 1 MODIFIED NCD SWITCH 1 12 POTENTIAL ENERGY COMPONENTS
FROM BONDED INTERACTIONS Stretch Flex Torsion POTENTIAL ENERGY
COMPONENTS FROM NON-BONDED INTERACTIONS Coulomb Interaction SWITCH
1 P-LOOP ADPSWITCH 1 SWITCH 2 P-LOOP THE OPEN SWITCH 1 CONFORMATION
IS STABLE P-LOOP SWITCH 1 P-LOOP SWITCH 2 THE CLOSED SWITCH 1
CONFORMATION IS STABLE MOLECULAR DYNAMICS RESULTS Open structure
(x-ray) stable at 300 K (ADP, ATP, APO) Closed structure (model)
stable at 300 K (ADP, ATP, APO) Closed Open Open and closed
structures Are local minima on a global free energy surface. Test
with high temperature Dynamics. GG Energy barrier INFLUENCE OF
SWITCH 1 ON EPR PROBES ANGLE ANGULAR DISTRIBUTION FOR SSL-NANDP IN
THE OPEN AND CLOSED CONFORMATIONS COORDINATION AT THE OPEN
NUCLEOTIDE SITE COORDINATION AT THE CLOSED NUCEOTIDE SITE MYOSIN
KINESIN CONCLUSIONS 1. Comparison with myosin suggests a new
structural state of kinesin-family motors involving a closing of
the nucleotide site. 2. Spectroscopic data show the nucleotide site
closes when kinesin binds to microtubules. 3. MD shows the open and
closed binding-site conformations of kinesin-family motors explain
the changes in mobility of nucleotide analog EPR probes upon
binding to microtubules. 4. MD shows the closed state is essential
for nucleotide hydrolysis and force production. COLLABORATORS ROGER
COOKE, UCSFRALPH YOUNT, WSU Nariman NaberXiaoru Chen Marija
MatuskaJean Grammer Kathy Franks-Skiba PETER KOLLMAN, UCSF RON
VALE, UCSF Todd Minehardt Sarah Rice ROBERTO CAR, PRINCETON DAVID
ADCOCK, LONE STAR BIOTECH
