Preliminary crystallographic study of macromomycin: The apoprotein of the antitumor antibiotic auromomycin

Macromomycin (M_r 12,000) is the apoprotein of the antitumor drug auromomycin, which inhibits DNA synthesis by causing single-strand breaks in DNA. Two orthorhombic crystal forms of macromomycin have been observed. The platelike crystals of one form belong to space group P2₁2₁2₁, with cell dimensions $\text{a = 48·92}\text{A}\text{?}\text{, b = 54·71}\text{A}\text{?}\text{, c = 103·31}\text{A}\text{?}\text{, Z = 8}$. The crystals of the second form are needle-shaped, and belong to space group P2₁2₁2, with cell dimensions $\text{a = 46·1}\text{A}\text{?}\text{, b = 54·4}\text{A}\text{?}\text{, c = 41·2}\text{A}\text{?}\text{, Z = 4}$. At this point in time, the platelike crystals appear the most suitable for continued crystallographic studies.