2. • Proteins from the same family are often characterized
by short conserved regions that are usually related
with function, such as binding sites or active sites.
• However, they are not usually detectable by sequence
search techniques such as BLAST or FASTA.
What is Motif ?
4. Sequence motif - a sequence pattern of nucleotides
in a DNA sequence or amino acids in a protein.
TYPES
5. Structural motif - a pattern in a protein structure
formed by the spatial arrangement of amino acids.
TYPES
6. • The Omega loop is a structural motif with any amino
acid sequence , with the only condition that it should
be able to form a stable structure that resembles the
greek letter “ω”. This makes the motif extremely
common, but nothing can be said about its
significance in the function of the protein.
Example
7. 7
Significance of Motif
• A disease can be easily eliminated permanently by using it
to develop new patterns of motifs.
• Early detection of a disease, by storing the amino-acid
structural motif from early detections case samples.
• Better analysis of protein, which will help in better
understanding of the different motif causing different
functions in a protein.
• Scientists will get a better tool to know more about a
disease, and can instruct experts and doctors for better
treatment and understanding.
8. What is Domain?
• Stable units of Protein.
• Conserved part of agiven proteinsequence.
• Decidesstructure and function of Protein.
• Folded 3-Dcompact structure withstability.
• Length vary between 25 to 500 amino acid.
9. 9
• A protein has a DNA binding domain located towards
the N terminus of the protein, and a catalytic domain
that is located closer to the C-terminus. Theoretically
one can separate the domains from each other and the
DNA binding domain will still bind DNA and the
catalytic domain will still perform catalysis.
Example
11. Significance of Domain
• Domains are independently stable, domains can be
"swapped" by genetic engineering between one protein
and another to make chimeric proteins.
• Metabolic Engineering can be placed by altering protein
domain.
• Better analysis of protein, which will help in better
understanding of the different domain causing different
functions in a protein.
12. Motif vs Domain
Motif Domain
Super secondary structure Tertiary structure
Formed by the connected alpha-
helices and beta-sheets through loops
Formed by the formation
of disulfide bridges, ionic bonds, and
hydrogen bonds between amino acid
side chains.
Mainly have a structural function in
the protein structure
Mainly have functional importance.
Perform similar biological functions
through a particular protein family
Have unique functions
Are not stable independently Independently stable
13. Similarities between Motif and Domain
• Both are units present in protein molecules themselves.
• They are useful when classifying protein families.
• They have both structural and functional importance in
the protein structure.
• Moreover, they are made up through the interactions of
alpha-helices and beta-sheets.
• Besides, both are 3D structures.
