Alexander Galkin

Bioenergetics




 

All around Bioenergetics

Grey Book, Bioenergetics, Mitchell

Peter Mitchell's Little Grey Book is available now from Biochimica et Biophysica Acta: Chemiosmotic coupling in oxidative and photosynthetic phosphorylation

I also recommend David Nicholls paper "Forty years of Mitchell's proton circuit: From little grey books to little grey cells"

MPTP, mitochondrial Complex I and William Gibson's Necromancer

MPTP, necromancer 
 
  "Peter's good as dead anyway," Molly said. "In another twelve 
hours, he'll start to freeze up. Won't be able to move, his eyes 
is all." 
     "Why?"Case turned to her. 
     "I poisoned his sh*t for him," she said. "Condition's like 
Parkinson's disease, sort of." 
     3Jane nodded. "Yes.  We  ran  the  usual  medicalscan, before he  was 
admitted." She touched the ball in a certain way  and  it sprang  away  from 
Molly's  hands.     "Selective   destruction  of  the  cells   of   the   substantia 
nigra. Signs of the formation of a Lewy body. He sweats a great deal, in his 
sleep." 
     "Ali,"   Molly   said,  ten  blades   glittering,  exposed  for  an   instant.  She
tugged    the  blanket   away  from   her   legs,  revealing   the   inflated  cast. 
"It's  the  meperidine. I  had  Ali make  me  up  a  custom batch. Speeded up 
the reaction times with higher temperatures. N-methyl-4-phenyl-1236," she 
sang, like a child reciting the steps of a sidewalk game, 
"tetra-hydro-pyridene." 
     "A hotshot," Case said. 
     "Yeah," Molly said, "a real slow hotshot." 
     "That's appalling," 3Janesaid, and giggled. 

                          from "Necromancer" by William Gibson, 1984 (read it here)

Apparently american Sci-Fi writer William Gibson was at the front of biochemical research of his time. MPTP or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine was first manufactured in 1947 and used mostly as a starting material for the synthesis of other organic substances. It was even tested as a possible treatment for Parkinson’s Disease (PD). In 1982 the effects of MPTP were discovered in a long chain of events when the particular batch of illegal synthetic meperidine drug (sold under the name of China White) induced Parkinson’s-like symptoms in several young drug users in Santa Clara County, California. Almost overnight they became “frozen” in a PD-like state [Langston at al., 1983 ]. Doctors were puzzled by these cases - the patients were too young and deteriorating too rapidly to suffer from clinical PD. After analysis of paraphernalia used by the drug addicts, consideration of their symptoms and autopsy results it turned out that MPTP was the key factor selectively toxic to the substantia nigra [Langston at al., 1983 ]. The substantia nigra is an area of the midbrain responsible for movement control and death of dopaminergic neurons in that area is the cause of Parkinson’s disease resulting in tremor, stiffness and slowness of motor movements. However, even as early as 1976, a young chemistry research student from Maryland, Barry Kidston, synthesised meperidine incorrectly which led instead to the production of the toxin MPTP. After testing his product on rats (rodents turned out to be much less sensitive to MPTP), he injected himself with his own product and within three days developed symptoms of Parkinsonism [Davis et al., 1979]. It has been shown that once taken up in the brain, MPTP is converted by monoamineoxidase (MOA-B) in glial cells into another compound, MPP+, which is transported by the dopamine transporter of surrounding neurons and inhibits the important cellular organelle, the mitochondria (Figure 1). MPP+ is a very weak inhibitor of mitochondrial Complex I but as a lipophilic cation (positively charged) it is accumulated into the mitochondrial matrix in accordance with the mitochondrial membrane potential (negative inside). Even if present in a nanomolar range outside the cells, MPP+ concentration in mitochondria could reach millimolar levels - enough to inhibit the enzyme. Interestingly, MPTP resulted in death even in flatworms, the most primitive species with a central nervous system, but not in rodents which lack the specific dopamine transporter.

MPTP, Parkinson's disease, Complex I


MPTP can cross the blood–brain barrier and is metabolized to MPP+ (1-methyl-4-phenylpyridinium) with the assistance of the enzyme monoamine oxidase B (MAO-B) in glial cells. MPP+ is then taken up by into neuronal cells dopamine transporter (shown green) for which it has high affinity. Once inside neurons, MPP+ is concentrated by an active electrophoretic transport within the mitochondria, where it impairs mitochondrial oxidative phosphorylation by inhibiting complex I of the respiratory chain.

Despite intensive research of Parkinson disease several questions remains to be answered:

  1. Why are dopaminergic neurons so sensitive especially to Complex I inhibition?
  2. What are the cause and the mechanism of selective inhibition of Complex I in PD ?
  3. Why is the activity of complex I lower not only in neurons of PD-patients but also in platelets from the blood?
  4. What is the relative role of possible oxidative stress, mitochondrial DNA damage or energy-deficit in the development of PD?
  5. How does MPP+ affect A/D conformational change of Complex I?


You could read further about that fascinating story in The Case of the Frozen Addicts book by J. William Langston


References:
Langston JW, Ballard P, Tetrud JW, Irwin I. (1983) Chronic Parkinsonism in humans due to a product of meperidine-analog synthesis. Science. 219, 979

Davis, G.C., Williams, A.C., Markey, S.P., Ebert, M.H., Caine, E.D., Reichert, C.M., Kopin, I.J., (1979) Chronic Parkinsonism secondary to intravenous injection of meperidine analogues. Psychiatry Res. 1, 249

Fishing, Thomas Mayne Reid and Complex I inhibitor rotenone 

rotenone, complex I 
 
  "Guapo now bethought himself of the narrow escape he himself had
 had while swimming across to the palm-woods and the appearance of 
the gymnotus only rendered him more determined to keep the promise 
he had made to Leon,- that is, that he would revenge him of the caribes. 
None of them could understand how Guapo was to get this revenge 
without catching the fish, and that would be difficult to do. 

Guapo, however, showed them how on the very next day.During that 
evening he made an excursion into the wood, and returned home 
carrying with him a large bundle of roots. They were the roots 
of two species of plants--one of the genus Piscidea, 
the other a Jacquinia. Out of these, when properly pounded together,
 Guapo intended to make the celebrated barbasco, or fish-poison, 
which is used by all the Indians of South America in capturing fish. 
Guapo knew that a sufficient quantity of the barbasco thrown 
into the water would kill either temblador, caribe, or any fish 
that ever swam with fins.

From The Forest Exiles by Mayne Reid 1854 (can be found here )

rotenone, mitochondrial Complex I
 

As mentioned by Thomas Reide, fishing by water poisoning using roots of some tropical plants was common in Amazonia  (in fact it still is, see video). Specific compounds called rotenoids are responsible for the poisoning of fish and can be found almost exclusively among legumes in the family Fabaceae. Rotenone (Fig 2), the best known member of the group, was first extracted by French botanist Emmanuel Geoffroy in 1895 under the name of nicouline (from a native plant of French Guiana called Robinia) [Geoffroy 1895].
 

The wide distribution of rotenone-containing plants explains why this toxicant has been used for a long time as a fish poison by people of many different cultures. The procedure was first documented among natives of the East Indies and South-East who crushed the roots of tuba plant (liana Derris elliptica), sometimes along with small shrimps, mixed it with human excrement and poisoned water in small rivers with this mixture [Rumphius 1747]. The employment of derris extract as an insecticide by gardeners in the East Indies has long been a common practice. The use of Derris elliptica extracts against leaf eating caterpillars during nutmeg cultivation was also reported [Oxley 1848].

 


In 1902 Kazuo Nagai in Japan extracted a crystalline substance from the roots of Derris chinensis, which he called rotenone from roh-ten which was the name of the plant in Taiwanese [Nagai 1902]. In 1929 rotenone was isolated from the roots of Peruvian plant Lonchocarpus sp., locally known as barbasco or cube. Lonchocarpus plants even became an export product as an insecticide due to their high content of rotenoids. In the beginning of the XX century rotenone was used as a remedial agent for combating mites, fleas and body lice on animals and as a killing agent for house flies and roaches [Ambros&Haag 1936] (see the 40's advertisment).




 
rotenone, pesticide, mitochondrial Complex I


Rotenoids are a special group of mitochondrial Complex I inhibitors. When rotenone is introduced to the water by mashing the part of the plants, it lyses fish gills and half-paralysed fish are forced to swim at the water surface where they can be easily caught. In early studies it was found that rotenone inhibits oxygen consumption in fish gill filaments, liver tissue slices and isolated liver mitochondria [Lidhal&Oberg, 1961]. It was found to be a powerful inhibitor of the mitochondrial aerobic oxidation of substrates linked to NAD without affecting succinate oxidation [Ernster et al, 1963]. Later, the target of rotenone was identified to be mitochondrial Complex I and it was used widely by researchers in the mitochondrial field. As with many hydrophobic substances inhibiting the enzyme, the rotenone molecule structurally resembles Complex I substrate ubiquinone in one of its folded forms. It is generally accepted that rotenone blocks the electron transfer between the terminal iron-sulphur cluster N2 of the enzyme and the ubiquinone pool. Most likely rotenone binds close to the ubiquinone-binding site of the enzyme preventing entrance of a substrate. Many of the common hydrophobic inhibitors of Complex I are found to share a common binding domain in the vicinity of ubiquinone binding site [Okun et al., 1999]. Due to the fact that interaction between the enzyme and rotenone is mediated through the membrane phase, its kinetic model cannot be described as classical competitive inhibition with ubiquinone. The kinetics of rotenone binding is not trivial and is characterised in terms of tightly-bound reversible inhibitor binding to two non-interacting binding sites with different affinities [Grivennikova et al, 2003].








 

References:

Ambrose A, Haag H (1936) Toxicological study of Derris. Ind. Eng. Chem. 28, 815

Ernster L, Dallner G, Azzone G 1963 Differential effects of rotenone and amytal on mitochondrial electron and energy transfer. J. Biol. Chem. 238, 1124

Geoffrey, E. 1895. Contribution à l'étude du Robinia Nicou Aublet, au point de vue botanique, chimique et physiologique”. Ann. Inst. Colon. Marseille 2, 1

Grivennikova VG, Roth R, Zakharova NV, Hägerhäll C, Vinogradov AD. (2003) The mitochondrial and prokaryotic proton-translocating NADH:ubiquinone oxidoreductases: similarities and dissimilarities of the quinone-junction sites. Biochim Biophys Acta. 1607, 79

Lindahl P.E., Oberg K.E.(1961) The effect of rotenone on respiration and its point of attack. Exp.Cell Res. 23, 228

Nagai, K. (1902). Research on poisonous principles of rohton  J. Tokyo Chemi. Soc. 23, 744

Okun JG, Lümmen P, BrandtU.(1999) Three classes of inhibitors share a common binding domain in mitochondrial complex I (NADH:ubiquinone oxidoreductase. J Biol Chem. 274, 2625

Oxley T (1848) Some account of the nutmeg and its cultivation J. Indian Archipelago and East Asia, 10, 641

Rumphius GE (1747) Hermarium Amboinense, Vol 5, Amsterdam, 492.