Mr.G.ThirupugalMr.G.Thirupugal

II M.Sc., Microbial Gene TechnologyII M.Sc., Microbial Gene Technology

Department of Microbial TechnologyDepartment of Microbial Technology

School of Biological SciencesSchool of Biological Sciences

Madurai Kamaraj UniversityMadurai Kamaraj University

By

Designing a Peptide Aptamer to Unfold

Pancreatic Cholesterol Esterase - Treatment of Obesity

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

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.

How Is Obesity Treated?

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-yellow-

red-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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