structure of mitochondria

outer membrane 外膜
inner membrane 内膜
intermembrane space 膜间隙
matrix 基质

alt text

outer membrane

contains porin 孔蛋白

highly permeable
高度可透,如ATP,NAD,CoA

inner membrane

impermeable

contain protein with 3 type of function

  1. Electron-transport chain
    电子传递链
    Carry out oxidation reactions
  2. ATP synthase
    在matrix中合成ATP
  3. Transport proteins
    允许代谢物通过
    Allow the passage of metabolites

matrix

  1. the site where chemical reactions occur
    比如pyruvate丙酮酸 and fatty acid脂肪酸的氧化

  2. DNA replication , RNA transcription

alt text

alt text

ATP synthase

structure

存在于inner membrane上,头朝着matrix

alt text

F1

hydrophilic

5种9个亚基
α3 β3 γ Ɛ δ

α和β都能结合ADP,只有α能催化ATP合成

γ forms central stalk 中间轴

γ和Ɛ form rotator 转子

a b δ form the peripheral stalk 外周柄

F0

hydrophobic

3种亚基a b c constitute a proton channel

a b2 c8~15

c is proton channel

只有这一圈c是在转的,其他都是固定的

mechanism

alt text

用H+流动drive conformational change

β 有3种conformation
Loose,Tight,Open

rotor转子每转120°构象变化一次,合成一个ATP

generation of H+ gradient

通过electron transport电子传递链,高能电子逐渐变成低能电子,同时把H+从matrix泵到intermembrane space

低能电子最终与O2形成H2O

alt text

Electron Transport Chain 电子传递链

电子从NADH来
NADH → NAD+ + H+ + 2e-

alt text

电子路径
Complex I and II → UQ → Complex III → Cytc → Complex IV

Three H+ pumps
Complex I, III, IV

Phosphorylation in ATP synthesis is coupled with electron transport, so the process of ATP synthesis in mitochondria is called oxidative phosphorylation
ATP合成的过程伴随着电子传递因此也叫氧化磷酸化