Crystallization and preliminary X‐ray study of native and selenomethionyl β‐1,4‐mannanase AaManA from Alicyclobacillus acidocaldarius Tc‐12‐31

AaManA, a β‐1,4‐mannanase from the thermoacidophile Alicyclobacillus acidocaldarius Tc‐12‐31, was expressed in Escherichia coli and purified in a form suitable for X‐ray crystallographic analysis. Crystals were obtained using the hanging‐drop vapour‐diffusion method at 291 K using ammonium dihydrogen phosphate as a precipitant. Data were collected from native mannanase and from a selenomethionyl derivative to 1.90 and 1.99 Å, respectively, at 100 K. The native crystal belongs to the orthorhombic space group P 2 1 2 1 2 1 , with unit‐cell parameters a = 44.34, b = 75.55, c = 88.02 Å. The derivative crystal belonged to the same space group as native AaManA, with unit‐cell parameters a = 44.55, b = 75.70, c = 92.66 Å.