Transcript There is an old saying

Designing a Peptide Aptamer to Unfold
Pancreatic Cholesterol Esterase - Treatment of Obesity
By
Mr.G.Thirupugal
II M.Sc., Microbial Gene Technology
Department of Microbial Technology
School of Biological Sciences
Madurai Kamaraj University
INTRODUCTION

Overweight and obesity result from an energy imbalance.
This involves eating too many calories and not getting
enough physical activity.

Body weight is the result of genes, metabolism, behavior,
environment,

culture,
and
socioeconomic
status.
Behavior and environment play a large role causing
people to be overweight and obese. These are the greatest
areas for prevention and treatment actions
OBESITY

What is it?

How is it measured?

What causes it?

What are the health risks?

What can you do about it?
What Is Obesity?
Overweight
Overweight as an excess amount of body weight that includes
muscle, bone, fat, and water.
Obesity
Obesity specifically refers to an excess amount of body fat. Some
people, such as bodybuilders or other athletes with a lot of muscle, can
be overweight without being obese.
How Is Obesity Measured?
Measuring the exact amount of a person's body fat is not
easy. The most accurate measures are to weigh a person underwater or to
use an X-ray test called Dual Energy X-ray Absorptiometry (DEXA).
In recent years, body mass index (BMI) has become the medical
standard used to measure overweight and obesity.
What Is Body Mass Index
BMI uses a mathematical formula based on a person's height and
weight. BMI equals weight in kilograms divided by height in meters
squared (BMI = kg/m2).
A BMI of 25 to 29.9 indicates a person is overweight. A person
with a BMI of 30 or higher is considered obese.
Calculate Your Risk
Body Mass Index for Adults
Body Mass Index or BMI is a tool for indicating weight status in
adults.It is a measure of weight for height. For adults over 20 years old,
BMI falls into one of these categories:
BMI
Weight Status
Below 18.5
Underweight
18.5 – 24.9
Normal
25.0 – 29.9
Overweight
30.0 Above
Obese
What Causes Obesity
In scientific terms, obesity occurs when a person consumes
more calories than he or she burns. What causes this imbalance
between calories in and calories out may differ from one person to
another.

Genetic

Environmental

Psychological

Other Factors
Health Consequences

Approximately 280,000 adult deaths in the United States each year are related
to obesity.
Several serious medical conditions have been linked to obesity, including

Type 2 Diabetes

Heart Disease

High Blood Pressure

Stroke

Cancer
Diseases Linked to Obesity

Gallbladder disease and gallstones

Liver disease

Osteoarthritis, a disease in which the joints deteriorate. This is
possibly the result of excess weight on the joints

Gout, another disease affecting the joints

Pulmonary (breathing) problems, including sleep apnea in which a
person can stop breathing for a short time during sleep

Reproductive problems in women, including menstrual irregularities
and infertility
TREATMENT OF OBESITY
How Is Obesity Treated?
The method of treatment depends on your level of obesity,
overall health condition, and motivation to lose weight. Treatment may
include a combination of diet, exercise, behavior modification, and
weight-loss drugs. In some cases of severe obesity, gastrointestinal
surgery may be recommended.
FDA-Approved Prescription Weight Loss Drugs
Weight Loss Drug
Brand Name
Dexfenfluramine
Redux (withdrawn)
Diethylpropion
Tenuate, Dospan
Fenfluramine
Pondimin (withdrawn)
Mazindol
Sanorex, Mazanor
Orlistat
Xenical
Phendimetrazine
Bontril, Plegine, Prelu-2, X-Trozine
Phentermine
Adipex-P, Fastin, Ionamin, Oby-trim
Sibutramine
Meridia
Drugs For Obesity Treatment
Appetite-suppressant medications
Appetite-suppressant medications promote weight loss by
decreasing appetite or increasing the feeling of being full.
Inhibitors of Dietary Cholesterol absorption
In 1999, the drug orlistat was approved by the Food and Drug
Administration (FDA) as an obesity treatment. Orlistat works by
reducing the body's ability to absorb dietary fat by about one third.
Inhibitors of Dietary Cholesterol Absorption
PANCREATIC CHOLESTEROL ESTERASE
Pancreatic Cholesterol Esterase

Cholesterol esterase plays an important role in the dietary uptake of
triacylglycerol and cholesterol esters.

It presents major lipolytic activity that is secreted from vertebrate
pancreas into the intestinal tract.
Origin of the protein

Gene name - cel

synonyms- bal

EC 3.1.1.13
Synonyms

Bile Salt activated lipase

Carboxylester lipase

Sterol esterase

Pancreatic lysophospholipase
Function of Pancreatic Cholesterol Esterase
Pancreatic cholesterol esterase has three proposed functions in the
intestine.

To control the bioavailability of cholesterol from dietary
cholesterol esters.

To contribute to incorporation of cholesterol into mixed micelles

To aid in transport of free cholesterol to the enterocytes
Catalytic Action of Pancreatic Cholesterol Esterase
Hydrolysis of cholesterol ester in the lumen of the small intestine is catalyzed
by cholesterol esterase, which liberates free cholesterol. Free cholesterol mixes with
cholesterol contained in bile secretions to form the pool of absorbable cholesterol
Intestinal Cholesterol Absorption
Structure of Pancreatic Cholesterol Esterase

A crystal structure of the catalytic domain of human bile salt activated lipase
or cholesterol esterase (CEL) contain 538 residues.

The crystal structure belongs to space group p212121.

The protein shows an / hydrolase fold.

The catalytic triad ser194 - His435- Asp320
Surface Loops

420 loop residues 423-433

270 loop residues 270-285

70 loop residues 65-75

120 loop residues 115-125 it is necessary for a cholestryl ester substrate to
bind to cholesterol esterase
Structure of Pancreatic Cholesterol Esterase
Continue…
PDB ID
:
2BCE, 1F6W,1JMY
2BCE
In silico Analysis of Cholesterol Esterase
 Secondary Structure Prediction
 Multalign analysis
 3D Structure analysis

Cn3D 4.1

UCSF Chimera

Chemera
Multalign Analysis of Bovine and Human
Cholesterol Esterase
Analysis of Charge Distribution -Cholesterol Esterase
The proteins positively charged residues in blue, negative in red and
neutral in gray
Analysis of Hydrophobicity
The proteins uses a standard hydrophobicity scale.The most hydrophobic
residues in red to the least hydrophobic (most hydrophilic) in blue
Analysis of Temperature
Uses a traditional temperature color cycle (blue-green-yellowred-white) to indicate relative temperature factors for each atom where
blue is lowest and white highest temperature
Target Screening
Analysis of Target Residues
Target amino acid sequence
SPYNKGLIRRAISQSGVALSPWVIQKNP
Charge
Hydrophobicity
Temperature
Designing of an Aptamer
Discovery:
The
Aptamers
discovered
by
Tuerk
&
Gold
and
subsequentlyby Ellington & Szostak in 1990. But the therapeutic
Aptamer has entered clinical evaluation just eight years after the
inception of the technology (1998).
Peptide Aptamers represents a distinct class of molecules
that are binding to a target protein and can block its activity
selectively. They thus represents a powerful alternative to
traditional approaches e.g., Knockout or mutation of a gene.
Designing Of An Aptamer
Overview of the SELEX Process
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