BIOC13H3 Lecture Notes - Lecture 16: Electrochemical Gradient, Coenzyme Q10, Nadh Dehydrogenase
BIOC13:(Lecture(18( ( Final(
March(21,(2018(
60#
Electron)Transport)Network)II!
!"#$%&'()*&+(,-'&%).#%/'&0)
*1#&2'34(+25$)+(3)65(#%5$)7'(,53#&+%5'(,)
Thermodynamic-Factors-
• Redox#centers#have#different#
reduction#potentials#
• Complex#I#has#the#lowest#reduction#
potential#and#this#potential#
increases#as#you#go#further#through#
the#complexes#
• Means#that#more#and#more#free#
energy#is#released#with#every#step#as#
moving#electrons#to#complexes#with#
higher#reduction#potentials#releases#
more#energy#
• The#energy#is#used#to#create#a#
proton#gradient#that#can#later#be#
used#to#generate#more#ATP#
Kinetic-Factors-
• The#distance#between#redox#centers#
cannot#be#too#far#or#else#electron#
transfer#will#be#too#slow#
o As#a#rule,#anything#further#than#14Å#is#too#far#
7'2-"#8)9):.;<=>?)@85A$%+,#B)
• Complex(I#oxidizes#an#NADH#and#passes#the#electrons#to#Q#(ie.#ubiquinone),#
thereby#reducing#it#
• Free#energy#is#released#for#proton#pumping#
Structure-
• It#have#46#subunits#
o 14#core#(missing#one#of#these#and#protein#won’t#function#properly)#
o 32#accessory#(not#necessary#for#basic#function#but#help#for#optimal#
function)#
• Can#be#divided#into#2#basic#domains:#peripheral#and#membrane#
• Peripheral(domain#is#hydrophilic#and#allows#it#to#stick#to#the#matrix#
o This#is#where#NADH#oxidation#occurs#and#electron#transport#to#Q#
• Membrane(domain#is#embedded#in#the#IMM#and#therefore#hydrophobic#
o It#does#the#proton#pumping#
• Provides#physical#link#between#redox#and#proton#pumping#
o Not#100%#sure#how#this#occurs#but#believe#that#redox#causes#
confirmation#change#that#stores#energy#and#used#to#pump#proton#(store#
energy#in#that)#