Proteomics Of Lactococcus Lactis Microbiologystudy

Mark Wilkins and colleagues coined the terms proteome and proteomics in the early 1990s.

The proteome is the complement protein or complete set of proteins expressed by the genome of an organism and is present in a single cell in a particular environment. It differs from cell to cell and varies through time.

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What is Proteomics?

Table of Contents

Proteomics, a new type of omics, is the study of the proteome.
The study of the protein composition, structure, function, interaction, and cellular activities is known as proteomics.

It mainly focuses on the organism’s structure and function than the genomics.
The protein expression varies with time and environmental conditions, which makes it more complicated than genomics.
Moreover, it is a multi-step technique, so it controls every step in the process to avoid non-biological factors interfering with protein expression and interaction.

The two classifications of proteomics are protein expression mapping and protein interaction mapping.

Techniques of Proteomics

There is a wide range of proteomics techniques. They are:

One-dimensional (1D) and Two-dimensional (2D) gel electrophoresis (2-DE)) for protein separation.

Gel-free high-throughput screening techniques include multidimensional protein identification technology, isobaric tagging for relative and absolute quantitation (iTRAQ), stable isotope labeling with amino acids in cell culture (SILAC), and an isotope-coded affinity tag(ICAT).
Antibodies-based methods, such as ELISA (Enzyme-linked immunosorbent assay), immunoprecipitation, immune-electrophoresis, and Western blot.
Chromatographic methods include ion exchange, size exclusion, and affinity chromatography. HPLC (High-Performance liquid chromatography) is a technique for analytical proteomics.

PAGE, Mass spectrometry methods
X-ray crystallography and nuclear magnetic resonance spectroscopy
Analytical, functional, and reverse phase microarrays.

Objectives of Proteomics

a. It helps in the separation of protein/ peptide.

b. It helps to identify and characterize the resolved protein by mass spectrometry (MS).

c. Proteomics helps to analyze protein expression at different levels, such as post-transcriptional, transcriptomic, and genomic levels, both qualitatively and quantitatively.

d. It helps in the analysis and application purposes.

e. It helps in the movement of protein between subcellular compartments.

Types of Proteomics

Structural Proteomics:

It involves building a body of structural information that predicts probable structure and potential function.
The techniques used in structural proteomics are Nuclear magnetic resonance spectroscopy and X-ray crystallography to determine the three-dimensional structure and structural complexities of functional proteins.
The nuclear pore complex study is one of the examples of structural proteomics.

Functional proteomics:

It involves studying the protein functions and analyzing the characteristics of molecular protein networks (protein partner’s interactions) present in a living cell through proteomics techniques.

Expression proteomics:

Expression proteomics involves the study of quantitative and qualitative expression of proteins between samples.
It specifies protein expression that differs between two conditions, such as patients and controls.
It helps to find specific proteins and new proteins of disease in signal transduction. It identifies the patterns of protein expression in different cells.

An example is comparing tumor tissue samples to normal tissue to identify protein level differences. The detection technique is 2-DE and mass spectrometry (MS).

Introduction of Lactococcus lactis

Lactococcus lactis, a member of the mesophilic group, is a gram-positive, catalase-negative, facultatively anaerobic, nonmotile, and non-spore-forming bacterium with a G+C content of ∼35 mol%, which can grow at 10°C but not at 45°C. Hexose diphosphate pathway producing l (+)-lactic acid ferment glucose.
Lactococcus lactis, the primary organism for lactic acid bacteria (LAB), encounters three environmental stimuli such as H+, lactate, and undissociated lactic acid during fermentation. It is due to the accumulation of lactic acid (the predominant fermentation product). Lactic acid inhibits the growth of cells and accumulates essential products, such as nisin.

Lactic acid bacteria, non-pathogenic, are widely used in fermented food and pharmaceutical production. It is potential for new biomedical applications such as vaccine delivery, gene delivery, heterologous protein expression, and therapeutic drug delivery. Lactic acid bacteria are generally recognized as safe (GRAS).
It has the property of a simple mechanism, rapid growth, and lacks toxic substances.