1987 PROGRAM 3? g' B
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P M :3 E g Thirteenth Annual Symposrum on
A.M.  ' s O H-
12:15 Buffet Lunch Faculty Club 3: Ha
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9 00 RSI-gislggtion and 0 98 em stry ysics (Please return card by April 15, 1987 for M: 7: 9"
 reservation. Cost $6.00 to be paid at 4: g 0
9:30 Welcome by Dean Wimberly C. Royster registration.) O "" :T .
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Vice-Chancellor for Research. University of g 0 3 Che ISt and
Kentucky Chemistry Physics Rm 139 1:30 Dr. Harry B. Gray. California Institute of CN 5 __,, .
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Technology a s: Molecular Biology
9:35 Introductory Remarks Long-Range Electron Transfer in Heme Q \C
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9:40 Dr. George McLendon, University of ro e ns 0'!
Rochester Kinetic experiments at Northwestern, Rochester, Brookhaven, , . ,
Birds Do It, Bees Do It: How Does Biology and Caltech have conclusively shown that electrons can be transfer- / , . , I,
Transport Electrons? red relatively rapidly over large distances (greater than 10 , , , , , f _ 5, . ._
Biological energy is channeled via a series of simple electron angstroms) in proteins. Current research focuses on the factors established 111' the memory "of
transfer reactions. A brief overview will be presented of how elec- :Zhggzrmlgetdii: it: 022:: long-ralnge eleEtron transfters m ( Anna S . Naff
tron transfer occurs over long distances in simple chemical systems. th . p dtf. d I: b' cgmr: EXES' xpherrmen S on , ,, f , . ,
This work demonstrates that electron transfer reactions can occur n; tehnrumimo ll: {on O '35 :n W 0C rotmest av: examrnc; "
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rapidly (<1065 1) even when the reactants do not collide and are e et'ro es Th 5 arlce anth one; acep :r 5 fl: Lires an 
widely separated (eg 15 A). The recent results fully support the (grease 1C: ZZfererdifdons. 15 wor a: ll OW; t: are em ELECTRON TR NSFER
-r d' t' d b M d H 1" 1d t'  e cron- ra ecrease exponen 1a y W] e omr ,_ . . A
F e 1C ions ma 2 y arcus an op 1e some rme ago acceptor edge-to-edge distance. Evidence that an intervening , ' .
10:40 Break aromatic residue enhances long-range donor-acceptor electronic , I
1050 Dr William H Orme-Johnson coupling has been obtained in studies of electron transfer from  IN ,
' ' Massachusetts. Institute of Tedhnolo the excited triplet state of a zinc porphyrin to a ruthenium accep-
Electron Transfer and Biolo ical Nita: en tor in a doubly substituted myoglobin. Recent work involving METALLOPROTEINS
Fixation g g systematic variations in donor-acceptor energetics has defined ex- , , L, 
In organisms that can utilize metabolic energy derived from car perimentally the reorganization energies for protein electron *
 transfer , ' .
bohydrate metabolism to carry out the reduction of atmospheric  f '
nitrogen to ammonia, a specialized set of enzymes oxidizes 2:30 Break S k . .  .
pyruvate and conveys to dinitrogen the reducing equivalents thus 240 Dr. Brian M Hoffman Northwestern pea ers , g '
obtained. Through the four proteins participating directly in this University  71" 9 ' f f
process, the eight electrons ultimately used during the reduction Long-Range Electron Transfer Between HARRY B GRAY
of one N2 molecule are passed one at a time. For the case of the Pr / ,. , . - . ,
oteins ,
free-living nitrogen fixer Klebsiella pneumoniae, an essentially com- W _ th t h . f t l l t 'th' BRIAN M HOFFMAN
plete genetic analysis suggests that seventeen genes are required h epfgeeusr:g t : efclonrque 0 (me 252?; alceinent WI :1 GEORGE MCLENDQN
to synthesize and regulate the components of the nitrogen fixa~ , emo ins O S u y 0 rig-range cat e ec ro-n- unne _  f I _
tion system. Using the tools of genetic engineering as well as spec ing in protein complexes that incorporate redox centers rigidly held WILLIAM H ORME JOHNSON
troscopic procedures the nature of the prosthetic groups required fixed at crystallographically known distance and orientation. One
for electron transfer and the chemistry they catalyze is being ex- system we emplohy rs thimledclmtl hyrrrddhefrjnglobin; hav- '_
plored. Novel features of this complex system, perhaps of more lnhg onefype o C Iarrtrhsu :trtrem thb adc 0159 dsd: meta of:
general significance, include the use of metal centers to do the Eh yrrn, orlexargr: e e [ nt eh ] y r1 5. :la 'tloln :efiL: 2; ,
2e'/le' transformer separation normally carried out by flavins, the :2 cromp ex e wee: cy 9C ET: 2 an (1: a Hsu S l ,5 Monday: Apnl 24! 1987
utilization of a low molecular weight protein electron carrier cy OC rome E peroxr ase, m w lc case we irec y mom or De artment of Chemistr-
long-range intermolecular electron transfer between roteins that p y
(flavodoxin) operating at nearly diffusion - controlled rates. the l d W f d h _ , .p h , U . t f K t k
coupling of MgATP hydrolysis to low potential electron transfer, are natilrra reh ox pafrtners. H e in t at varratronsbin t ecriaroterg nrversr y 0 en LlC y
and the accumulation of multiple elections in 19' storage sites in matrixt roug use 0 natura y occumng variants or y srte- rrecte r 02 Lexington, Kentucky 40506-0055
the Nz-reducing component mutagenesrs can dramatically alter electron transfer rates. v 3 :3
~ to 5' C 3
11:50 Discussion 3:40 Discussion a E 'v E: g?
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4:00 Social Hour, Chemistry-Physics, Rm. 137 g p: 5'- g .30
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We encourage symposium participants, especially students, to E 22;.
take this opportunity to meet with the speakers. =