passages.id: split_5_test_1459_passage
passages.type: progene_text
passages.text: Of the six " hot - spot " residues identified ( Leu - 30 , Arg-33 , Arg-144 , Ala-145 , Met-148 , and Arg - 149 ) , four are located on the E-helix , which is located at the center of the binding site flanked by residues on the A-helix and the AB - loop .