4BLC image
Deposition Date 1998-09-27
Release Date 1998-10-14
Last Version Date 2023-09-13
Entry Detail
PDB ID:
4BLC
Keywords:
Title:
THE STRUCTURE OF ORTHORHOMBIC CRYSTALS OF BEEF LIVER CATALASE
Biological Source:
Source Organism:
Bos taurus (Taxon ID: 9913)
Method Details:
Experimental Method:
Resolution:
2.30 Å
R-Value Free:
0.27
R-Value Work:
0.20
R-Value Observed:
0.20
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:PROTEIN (CATALASE)
Gene (Uniprot):CAT
Chain IDs:A, B, C, D
Chain Length:506
Number of Molecules:4
Biological Source:Bos taurus
Primary Citation
Structure of orthorhombic crystals of beef liver catalase.
Acta Crystallogr.,Sect.D 55 1383 1394 (1999)
PMID: 10417406 DOI: 10.1107/S0907444999007052

Abstact

The growth mechanisms and physical properties of the orthorhombic crystal form of beef liver catalase were investigated using in situ atomic force microscopy (AFM). It was observed that the crystals grow in the <001> direction by an unusual progression of sequential two-dimensional nuclei of half unit-cell layers corresponding to the 'bottoms' and 'tops' of unit cells. These were easily discriminated by their alternating asymmetric shapes and their strong growth-rate anisotropy. This pattern has not previously been observed with other macromolecular crystals. Orthorhombic beef liver catalase crystals exhibit an extremely high defect density and incorporate great numbers of misoriented microcrystals, revealed intact by etching experiments, which may explain their marginal diffraction properties. To facilitate interpretation of AFM results in terms of intermolecular interactions, the structure of the orthorhombic crystals, having an entire tetramer of the enzyme as the asymmetric unit, was solved by molecular replacement using a model derived from a trigonal crystal form. It was subsequently refined by conventional techniques. Although the packing of molecules in the two unit cells was substantially different, with very few exceptions no significant differences in the molecular structures were observed. In addition, no statistically significant deviation from ideal 222 molecular symmetry appeared within the tetramer. The packing of molecules in the crystal revealed by X-ray analysis explained in a satisfying way the process of crystal growth revealed by AFM.

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