Chris Farley Shannon Hoon River Phoenix What did

Chris Farley Shannon Hoon River Phoenix

What did they have in common? They were all cocaine addicts and they died of cocaine overdose!

COCAINE ESTERASE (coc. E) The story of the ‘dope fiend’ Rhodococcus bacteria. By: Gladys de Leon Department of Chemistry and Biochemistry University of Guelph

Overview n general description of Cocaine n Brain mechanism under influence of cocaine n Effects and dependency n Coc. E overview n Structural and biochemical analysis of coc. E n Concluding remarks

Structure of cocaine

What is cocaine? n C, coke, snow, nose, candy, crack n powerful central nervous system (CNS) stimulant n provides intense feelings of pleasure n Derived from leaves of South American coca bush (erythroxylon coca and erythroxylon novogranatense) n Addictive and can cause death

Erythroxylon coca cultivated in Bolivia, Peru and Ecuador n grows to a height of up to eight feet n rich in vitamins, protein, calcium, iron and fibre n cocaine content of the leaves ranges from O. 1% to 0. 9% n http: //cocaine. org/cokleaf. html

History of cocaine n n n n Used by man since 800 A. D. Cultivated by the Incan 1500 s - Coca chewing of the South American Indians 1860 s - Isolated from coca leaf by Albert Nieman 1880 s - Sigmund Freud’s Uber Coca 1886 - Coca Cola a non-alcoholic medicinal tonic from Atlanta Georgia 1890 s – Cocaine containing medicine 1922 – Narcotic Drug Import and Export Act restricted coca imports

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1 Kg of Cocaine

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How does Cocaine affect the brain?

The Dopamine Hypothesis F. I. Carroll et al, Journal of Medical Chemistry 42, 2721 -36 (1999)

The brain NA – nucleus accumbens VT – ventral tegmental FC – frontal cortex CB – cerebeller PT – putamen CN- caudate nucleus F. I. Carroll et al, Journal of Medical Chemistry 42, 2721 -36 (1999)

What are the effects of cocaine on the mind? n Thinking and feeling brain n Racing thoughts n Reward n Felling of well being

!! EUPHORIA !! Negative effects: Increased heart rate Hyperthermia Dilated pupils Diaphoresis Irritability Decrease appetite Sleeplessness Depression Over dose: respiratory arrest Myocardial infarction Arrhythmia Seizures

Cocaine Dependency : Three classical clinical characteristics that define addiction Psychological dependence 2. Tolerance 3. Physical withdrawal 1.

1. Psychological dependence n Compulsive drug seeking behavior despite negative consequences n Drug becomes the highest priority in the individual’s life

2. Tolerance n As time goes on, more and more of the drug is needed to produce the same high

3. Physical withdrawal n Constellation signs and symptoms that occur following cessation of drug use

Emergency Situation COCAINE OVERDOSE

So what is an ideal cocaine antidote in an emergency setting? n High catalytic proficiency n Lack of observable product inhibition n Ability to hydrolyze both cocaine and cocaethylene

Cocaine Esterase (coc. E) is an attractive candidate for rapid cocaine detoxification in an emergency setting.

Overview of coc. E: Identified in the bacteria Rhodococcus sp. Strain MB 1 (Rhodococcus thrives in the rhizosphere soil of the cocaine-producing plant Erythroxylum coca) n Cocaine degrading enzyme n First enzyme in the metabolic pathway leading to cocaine catabolism n Inducible and specific for cocaine n

Hydrolysis of cocaine by coc. E D. W. Landry et al, Science, 259, 1899 -1901

Cocaine Transition-State Analogues—Abzyme Formation

Structural and Biochemical Characterization of Cocaine Esterase (coc. E)

Structural Overview of coc. E n Belongs to the / hydrolase superfamily n 574 amino acids n ~65, 000 Daltons n 3 domains – (DOM 1, DOM 2, DOM 3) n 30 % -sheet n 23 % -helix

What is the structure of coc. E? N. A. Larsen et al. , Nature Structural Biology 9, 17 -21 (2002)

Domain Structure and Association

Domain 1: / sandwich Residues 1 -144 and residues 241 -354 n Hydrolase fold (repeating - - motifs) n Central -sheet is predominantly parallel n Contains the active site His-287 n N. A. Larsen et al. , Nature Structural Biology 9, 17 -21 (2002)

REVIEW N. A. Larsen et al. , Nature Structural Biology 9, 17 -21 (2002)

Domain 2: The -helical domain n n N. A. Larsen et al. , Nature Structural Biology 9, 17 -21 (2002) 95 amino acids Compose of 7 helices Inserted between 6 and 7 of Domain 1 Five helix core – helices H 2 -H 6

REVIEW N. A. Larsen et al. , Nature Structural Biology 9, 17 -21 (2002)

Domain 3: jelly-roll -barrel n n n N. A. Larsen et al. , Nature Structural Biology 9, 17 -21 (2002) 221 amino acids Overall fold has a jelly-roll -like topology ( i. e. Hgg. Haemagglutinin) Mostly -structure -barrel-like core Strands connected by 6 cross over loops Important role in the overall tertiary structure

Active site of coc. E n n n N. A. Larsen et al. , Nature Structural Biology 9, 17 -21 (2002) Located in a cleft formed at the interface of the three domains Catalytic triad – Ser 117, Asp 259 and His 287 Oxyanion hole – backbone amide of Y 118 and Y 44

Proposed Mechanism for acyl intermediate hydrolysis

Biochemical Characterization and Structural Analysis of coc. E n n n coc. E hydrolyzes cocaine faster than any other reported cocaine esterase Follows Michaelis-Menten kinetics with kcat= 7. 8 s-1 and Km 640 nm. Similar rate for cocaethylene Validated the proposed mechanism Reveal contributions of active site towards substrate recognition and catalysis

J. M. Turner et al. Biochemistry, 41, 12297 -12307 ( 2002)

In conclusion: coc. E enzyme itself has therapeutic potential as an enzyme-based treatment for cocaine overdose, furthermore, the crystal structure of the bacterial cocaine esterase provides a basis for further antibody engineering.

http: //cocaine. org/cokehell. html

References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. W. F. Borson and T. D. Hurley, Nat Struct Biol. 9, 4 -5 (2002). N. A. Larsen et al. , Nat Struct Biol. 9, 17 -21 (2002). J. M. Turner et al. , Biochemistry, 41, 12297 -12307 (2002). Larsen, N. A. , Zhou, B. , Heine, A. , Wirsching, P. , Janda, K. D. , and Wilson, I. A. J. Mol. Biol. 311, 9 -15 (2001) F. I. Carroll, L. L. Howell, and M. J. Kuhar, J Med Chem. 42, 2721 -2736 (1999). L. L. Howell and K. M. Wilcox, Perspectives in Pharmacology, 298, 1 - 6 (2000). A. M. Washton and M. S. Gold. “Cocaine: A clinician’s handbook”, The Guilford Press, New York. 1987. Pp. 73 -79. D. W. Landry et al. , Science, 259, 1899 - 1901 (1993). P. H. Earley. “The Cocaine Recovery Book”, Sage Publications, London. 1991, pp. 9 -35. L. M. Kamendulis et al. , Jour. Phar. Exp. Ther. , 279, 713 -717 (1996). M. R. Brzezinski et al. , Drug Metab Dispos. , 9, 1089 -1096 (1997). C. E. Mattes et al. , Addict Biol. , 2, 171 -188 (1998). http: //www. cocaine. org/cokeleaf. html http: //www. hc-sc. gc. ca/hppb/alcohol-otherdrugs/pube/straight/stimulants. htm http: //www. a 1 b 2 c 3. com/drugs/coc 03. htm