1I4U

THE C1 SUBUNIT OF ALPHA-CRUSTACYANIN

Summary for 1I4U

• Entry DOI: 10.2210/pdb1i4u/pdb
• Related: 1H91
• Descriptor: CRUSTACYANIN, SULFATE ION, (4S)-2-METHYL-2,4-PENTANEDIOL, ... (4 entities in total)
• Functional Keywords: lipocalin fold, antiparallel beta barrel, transport protein
• Cellular location: Secreted, extracellular space: P80029
• Total number of polymer chains: 2
• Total formula weight: 42040.94

Authors

Gordon, E.J.,Leonard, G.A.,McSweeney, S.,Zagalsky, P.F. (deposition date: 2001-02-23, release date: 2001-09-19, Last modification date: 2024-11-06)

Primary citation

Gordon, E.J.,Leonard, G.A.,McSweeney, S.,Zagalsky, P.F.
The C1 subunit of alpha-crustacyanin: the de novo phasing of the crystal structure of a 40 kDa homodimeric protein using the anomalous scattering from S atoms combined with direct methods.
Acta Crystallogr.,Sect.D, 57:1230-1237, 2001

PubMed Abstract: The previously unknown crystal structure of the C(1) subunit of the carotenoid-binding protein alpha-crustacyanin has been determined using the anomalous scattering available at 1.77 A wavelength to determine the partial structure of the S atoms intrinsic to the native protein. The resulting 'heavy-atom' phases, in conjunction with near-atomic resolution (d(min) = 1.15 A) data, were then used to initiate successful structure determination using a direct-methods approach. This is, to the authors' knowledge, the first time such a small anomalous signal ( approximately 1%) has been used to aid the determination of a macromolecular structure. As well as the structure itself, the methods used during data collection and those used in the elucidation of the sulfur 'heavy-atom' partial structure are described here. As predicted, the C(1) subunit adopts a tertiary structure typical of the lipocalin superfamily: an eight-stranded antiparallel beta-barrel with a repeated +1 topology. The beta-barrel has a calyx shape with the two molecules in the asymmetric unit interacting in such a way that the open ends of each calyx face each other, although they do not form a single elongated pocket. A comparison of this structure with those of other members of the lipocalin superfamily has allowed speculation as to the nature of carotenoid binding by the protein.

PubMed: 11526314
DOI: 10.1107/S0907444901009362

Experimental method

X-RAY DIFFRACTION (1.15 Å)