There are a few weak features in the current 2.8 E electron density map of CcP:cc(H) complex we would like to examine more closely. The interfact of CcP:cc(Y) and CcP:cc(H) should be very important for study of electron transfer. It appears that hydrophobic and van der Waals interactions are the predominant forces holding the CcP:cc(Y). Only one weak intermolecular hydrogen bond exists in the CcP:cc(Y) structure, in contract to CcP:cc(H) complex, which has three intermolecular hydrogen bonds, two of which are charge-medicated. But it is not easy to compare interface between CcP:cc(Y) and CcP:cc(H) using data extending to from different resolution limits. We hope to obtain a more highly refined structure which may help locate its position more accurately.