Open Prosite in a new web browser tab. Note that Prosite is not an NCBI tool and therefore cannot be directly accessed to through NCBI homepage. The interface offers a variety of searching options related to protein motifs. We will focus on searching for motifs in a protein sequence, an option available on the left lower part of the screen (Screen 1). The researchers have at hands the amino acid sequence of the normal CFTR protein, as deposited in the databases, in a FASTA format. Copy this sequence of the normal protein and paste it in the designated window in the lower part of the Prosite interface, and click “Scan” for the search to begin (sequence comparison) to find motifs in the sequence.