user: Question: What is the side-chain charge (Ph 7.4) for the amino acid with the 1-letter P?
Columns: ['Amino Acid', '3-Letter', '1-Letter', 'Side-chain polarity', 'Side-chain charge (pH 7.4)', 'Hydropathy index']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Alanine', 'Ala', 'A', 'nonpolar', 'neutral', '1.8']
SQL:

assistant: SELECT "Side-chain charge (pH 7.4)" FROM "Table" WHERE "1-Letter" = 'P';