Definition: In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.
Input: A recombinant form of aminopeptidase N (molecular weight 99 kDa) from Escherichia coli was crystallized by the hanging-drop vapour-diffusion method using ammonium sulfate as a precipitating agent. The crystals belong to the hexagonal space group P3 1 21, with unit-cell parameters a = b = 120.5, c = 171.0 Å . The crystals are most likely to contain one molecule in the asymmetric unit, with a V M value of 3.62 Å 3 Da À1 . Diffraction data were collected to 2.0 Å resolution using Cu K radiation from a rotating-anode X-ray generator.

Structural Biology and Crystallization Communications Crystallization and preliminary X-ray characterization of aminopeptidase N from Escherichia coli