>1i21A (A:) observed residues (from ATOM records)
mslpdgfyirrmeegdleqvtetlkvlttvgtitpesfcklikywneatvwndkkimqyn
pmvivdkrtetvaatgniiierkiihelglcghiediavnskyqgqglgkllidqlvtig
fdygcykiildcdeknvkfyekcgfsnagvemqir