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Human Gastric Lipase 1HLG

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Human Gastric Lipase 1HLG

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    1. Human Gastric Lipase (1HLG) Presented by Melanie Thomas, Ankur Patel, & Brett Williams Biocomputing 3100

    2. I. Background Information Melanie Thomas

    3. Gastric Lipase Function: Enzyme aiding in fat digestion Location of action: Secreted by the stomach

    4. How Gastric Lipase Works Gastric lipase catalyzes the hydrolysis of stored triacylglycerols Substrate: triacylglycerol Products: long chain fatty acid and glycerol No cofactors

    5. How Gastric Lipase Works Hydrolyze substrate Present in intersurface between water and lipids Conformational Change Enzyme binds to intersurface ( between water and lipids) Activation occurs Active site of lipase is exposed Lipase binds to intersurface Helix moves Substrate binds at active site

    6. Sources Organism Humans 1st mammalian lipase structure to be described Hydrolyzes 10-30% of fats in adults Most fats digested by pancreatic lipase Majority of mammals Rabbits Dogs Other Related Mammalian Lipases Lingual Rats

    7. Humans Premature infants 95% of dietary fat in human milk and infant formula is triglyceride Gastric lipase is main digestive enzyme 25-60% of total lipid digestion Pancreatic lipase is not fully developed Researching ways to modify enzyme to benefit babies born prematurely.

    8. Humans Obesity in America Health problems Hypertension Diabetes High Cholesterol Levels Fats are most difficult part of diet to digest Anti-obesity drugs Suppress appetite

    9. Diet Pills Aim to inhibit the action of digestive lipases Reducing fat absorption Blocks lipases active site Inhibiting triglyceride digestion

    10. Diet Pills Orlistat Specifically targeted to inhibit gastric lipase and other digestive lipases Made from lipstatin Covalent inhibitor of digestive enzymes Much research many clinical trials Must be taken with a meal Inhibited 46.6 91.4% of activity of gastric lipase Reduced 11-33% of fat absorption by the stomach

    11. Disease Deficiency of Lipase Health problems Gall Stones Heart Problems Minimum nutrient absorption Wolman Disease Cholesteryl Ester Storage Disease

    12. Disease Caused by storage of triglycerides in body Not being absorbed or removed Excess fats in feces Lipids build up in the cells, blood, and lymph and causes damage Many digestive system problems

    13. Special Applications Vitamins Patients with lipase deficiency Some Medical Conditions cause an absence of lipase Cystic Fibrosis Patients Post Surgery Patients Some Cancer Patients Supplements Corn has been engineered to produce gastric lipase Still a work in progress Under clinical trials

    14. II. Structure of Human Gastric Lipase Ankur Patel

    15. Crystal Structure Of Human Gastric Lipase PDB number: 1HLG (Human Gastric Lipase) Method used to determine structure: X-Ray diffraction

    16. General Structure Information Number of chains: 2 (chain A and chain B) Both are identical Amino acid chains Each chain composed of 368 amino acids (excluding gaps) 379 amino acids with gaps included Gap 1: from amino acid 1 8 (8 residues) Gap 2: from amino acid 54 - 56 (3 residues) Total of 46 helices Total of 19 strands 2 total disulfide bridges

    17. Structure Showing Gaps 1 and 2 Shows only chain A Gap 1 = at N- terminus Gap 2 = 54- 56 residuesGap 1 = at N- terminus Gap 2 = 54- 56 residues

    18. Helices CHOFAS:

    19. Helices Cn3D

    20. Helices Protein Explorer

    21. Compiling information from Chofas, GOR4, PELE, Cn3D and Protein explorer Notice that each method shows a different number of helices Chofas, GOR4 and Pele only PREDICT helices The prediction algorithms show fewer helices than Protein explorer Protein explorer determines the helices by looking at the actual crystal structureProtein explorer determines the helices by looking at the actual crystal structure

    22. Strands CHOFAS Note: lot of overlaps between strands and helices which is not possible. Thus, Chofas is not the best method to calculate the number of strands present. Note: lot of overlaps between strands and helices which is not possible. Thus, Chofas is not the best method to calculate the number of strands present.

    23. Strands Cn3D

    24. Strands Protein Explorer

    25. Compiling information from Chofas, Pele, GOR4, Cn3d and Protein Explorer Biology workbench algorithms predict a high number of strands in each chain. The results from protein explorer and Cn3d show less strands

    26. Disulfide Bridges 2 total disulfide bridges Each is an intra-chain disulfide bridge Disulfide bridge: between cysteine 227 and cysteine 236 Common to find disulfide bridges between cysteien residues because cysteine has SH group. The SH sulfhydrl groups of two cysteine molecules can undergo oxidation to form a disulfide bridge. Common to find disulfide bridges between cysteien residues because cysteine has SH group. The SH sulfhydrl groups of two cysteine molecules can undergo oxidation to form a disulfide bridge.

    27. Ligand Animation

    28. Domains 2 Domains present Globular/core domain (colored purple) belongs to the alpha/beta hydrolase-fold family Between residues 9 189 Between residues 307 379 Cap domain (colored blue) Between residues 190 - 286 Shown by BLIMPS Shown by BLIMPS

    29. Alpha/beta hydrolase fold family: All have a classical catalytic triad; (Ser-153, His-353, Asp-324) Posses an oxayanion hole (stabilizes the oxayanion hole transition state). Hydrogen bonds between 2 main chain groups The cap domain has a lid. Covers catalytic SER-153 SER-153 is therefore not freely accessible to substrates Lid must be displaced in order for substrate to bind to catalytic SER-153 Info from research paperso did prosearch to prove thisInfo from research paperso did prosearch to prove this

    30. PROSEARCH Motif of interest: Lipase_SER Confirms presence of catalytic triad Typical catalytictriad (Ser-153, His-353, Asp-324). The catalytic serine is deeply buried under a segment consisting of 29residues the Lid. Triglyceride lipases are lipolytic enzymes that hydrolyzes the ester bond of triglycerides. The most conserved region is centered around a serine residue which has been shown to participate, with an histidine and an aspartic acid residue. which can be defined as a lid and belonging to the cap domain Triglyceride lipases are lipolytic enzymes that hydrolyzes the ester bond of triglycerides. The most conserved region is centered around a serine residue which has been shown to participate, with an histidine and an aspartic acid residue. which can be defined as a lid and belonging to the cap domain

    31. Different angles shown. Lid covers the SER 153 deep into enzymeDifferent angles shown. Lid covers the SER 153 deep into enzyme

    32. Active Sites One active site per chain in the core domain Residues: SER 153; ASP 324; HIS 353.

    33. Active Site

    34. Dog Gastric Lipase (1K8Q) Structure has been crystallized with a phosponate inhibitor. C11 - Undecyl-Phosphinic Acid Butyl Ester Makes crevice BOG - B-Octylglucoside Fills up remainder of crevice

    35. Interaction of Inhibitor and Catalytic Serine Reverse viewReverse view

    36. Human (1HLG) vs. Dog Gastric Lipase (1K8Q) Human on left Dog on right Note differences in lid conformationHuman on left Dog on right Note differences in lid conformation

    37. TMAP, GREASE, TMHMM Reveals no transmembrane segment

    38. III. Phylogeny / Homology Brett Williams

    41.

    43. Human Gastric Lipase (1HLG) vs Dog Gastric Lipase (1K8Q)

    44. Polyhydroxyalkanoates (PHA) Analyzing the similarities b/w Human Gastric Lipase & Type II Pseudomonas sp. USM 455 PHA synthase 1 Catalyzed by PHA synthase Biodegradable polyesters made from microorganisms

    45. Predicted PhaC1P.spUSM 4-55

    46. MSA including Pha C1 Synthase

    47. References Carriere,F., Renou, C., & Ransac, S. (2001). Inhibition of gastrointestinal lipolysis by Orlistat during digestion of test meals in healthy volunteers [ Electronic version]. AJP Gastrointestinal and Liver Physiology, 281, 16-28. Pafumi, Y., Lairon, D., & Lechenedela Porte, P. (2001). Mechanisms of Inhibition of Triacylglycerol Hydrolysis by Human Gastric Lipase [Electronic Version]. The Journal of Biological Chemistry, 277, 28070-28079. Roussel, A., Canaan, S., and Egloff, M. (1999). Crystal Structure of Human Gastric Lipase and Model of Lysosomal Acid Lipase, Two Lipolytic Enzymes of Medical Interest [Electronic Version]. The Journal of Biological Chemistry, 274,16995- 17002. Wahab HA, Bahiyah N, Khairudin A, Samian MR, Najimudin N: Sequence analysis and structure prediction of type II Pseudomonas sp. USM 4-55 PHA synthase and an insight into its catalytic mechanism. BMC Structural Biology 2006, 6:23. http://www.ncbi.nlm.nih.gov/Structure/vast/vastsrv.cgi?sdid=39042 http://www.gate2biotech.com/polyhydroxyalkanoates-the-biodegradable-plastics/

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