Explanation: Pattern Searching is the correct name of the method for finding localized sequence similarity. This type of analysis was performed on groups of related proteins, and the amino acid patterns that were located may be found in the Prosite catalog.

Explanation: For the 10-residue DNA sequence example, there are 100 – 20 +1 possible starting sites for a 20-residue-long site. Where the first one is at position 1 in the sequence ending one at 20 and the last beginning at position 81 and ending at 100 (there is not enough sequence for a 20-residue-long site beyond position 81).

Explanation: MACAW is both a local multiple sequence alignment program and a sequence editing tool. Given a set of sequences, the program finds ungapped blocks in the sequences and gives their statistical significance. Later versions of the program find blocks by one of three user-chosen methods.

Explanation: There are unique requirements for implementing algorithms for sequence database searching out of which, the later three play an important role. However, speed can vary with the size of database. achieving all three at a time is nearly impossible.

Explanation: BLAST is a family of programs that includes BLASTN, BLASTP, BLASTX TBLASTN, and TBLASTX. BLASTN queries nucleotide sequences with a nucleotide sequence database. The alignment scoring is based on the BLOSUM62 matrix.

Explanation: The string of residues is known as ktuples or ktups, which are equivalent to words inBLAST, but are normally shorter than the words. Typically, a ktup is composed of two residues for protein sequences and six residues for DNA sequences.

Explanation: In addition to this, user friendly UI of BLAST is also one of its benefits. However, it does not handle gaps well. In that case gapped BLAST is better.

Explanation: Residues in the loop or coil regions tend to be charged and polar and located on the surface of the protein structure. They are often the evolutionarily variable regions where mutations, deletions, and insertions frequently occur. They can be functionally significant because these locations are often the active sites of proteins.

Explanation: Visually appealing images can be generated that are of publication quality. The drawback is that the program is command-line–based and not very user friendly. A modified UNIX program called Bobscript is available with enhanced features.

Explanation: The SCOP families consist of proteins having high sequence identity (>30%). Thus, the proteins within a family clearly share close evolutionary relationships and normally have the same functionality. The protein structures at this level are also extremely similar.

Explanation: A neural network is trained not by a single sequence but by a sequence profile derived from the multiple sequence alignment. This combined approach has been shown to improve the accuracy to above 75%, which is a breakthrough in secondary structure prediction. The improvement mainly comes from enhanced secondary structure signals through consensus drawing. The following lists several frequently used third-generation prediction algorithms available as web servers.

Explanation: Coiled coils have an integral repeat of seven residues (heptads) which assume a side-chain packing geometry at facing residues. For every seven residues, the first and fourth are hydrophobic, facing the helical interface; the others are hydrophilic and exposed to the solvent. The sequence periodicity forms the basis for designing algorithms to predict this important structural domain.

Explanation: They are based on single sequence statistics without clear relation to known protein-folding theories. The predictions solely rely on local sequence information and fail to take into account long range interactions. A Chou-Fasman–based prediction does not even consider the short-range environmental information.

Explanation: As the name suggests, homology modeling predicts protein structures based on sequence homology with known structures. Homology modeling produces an all-atom model based on alignment with template proteins.

Explanation: The detailed procedure involves aligning the query sequence with each structural fold in a fold library. The alignment is performed essentially at the sequence profile level using dynamic programming or heuristic approaches. Local alignment is often adjusted to get lower energy and thus better fitting. The adjustment can be achieved using algorithms such as double-dynamic programming.

Explanation: Closing the gaps requires loop modeling, which is a very difficult problem in homology modeling and is also a major source of error. Loop modeling can be considered a mini–protein modeling problem by itself. Unfortunately, there are no mature methods available that can model loops reliably. Currently, there are two main techniques used to approach the problem: the database searching method and the ab initio method.

Explanation: It is known that RNA is a carrier of genetic information and exists in three main forms. They are messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). Their main roles are as follows: mRNA is responsible for directing protein synthesis; rRNA provides structural scaffolding within ribosomes; and tRNA serves as a carrier of amino acids for polypeptide synthesis.