PDBsum entry 2knt

Kunitz inhibitor

PDB id: 2knt

Contents

Protein chain

58 a.a. *

Ligands

PO4

Waters ×50

* Residue conservation analysis

PDB id:

2knt

Name:

Kunitz inhibitor

Title:

The 1.2 angstrom structure of kunitz type domain c5

Structure:

Collagen. Chain: a. Fragment: domain c5, c-terminus of type vi collagen. Engineered: yes. Other_details: kunitz-type

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: saccharomyces cerevisiae. Expression_system_taxid: 4932.

Resolution:

1.20Å R-factor: 0.149 R-free: 0.206

Authors:

K.Merigeau,B.Arnoux,A.Ducruix

Key ref:

K.Merigeau et al. (1998). 1.2 A refinement of the Kunitz-type domain from the alpha3 chain of human type VI collagen. Acta Crystallogr D Biol Crystallogr, 54, 306-312. PubMed id: 9761897 DOI: 10.1107/S0907444997010846

Date:

15-Jan-97 Release date: 15-May-97

Protein chain

P12111  (CO6A3_HUMAN) -  Collagen alpha-3(VI) chain from Homo sapiens

Seq: 3177 a.a.

Struc: 58 a.a.

DOI no: 10.1107/S0907444997010846

Acta Crystallogr D Biol Crystallogr 54:306-312 (1998)

PubMed id: 9761897

1.2 A refinement of the Kunitz-type domain from the alpha3 chain of human type VI collagen.

K.Merigeau, B.Arnoux, D.Perahia, K.Norris, F.Norris, A.Ducruix.

ABSTRACT

The recombinant Kunitz-type domain (C5) of human collagen alpha3(VI) chain was previously described at 1.6 A resolution at room temperature. By changing the crystallization conditions and using synchrotron radiation, we are able to record diffraction data to 1.2 A resolution for crystals of the same space group at 291 K. The protein-water-ion model has been refined anisotropically against these new data using the program SHELXL93; the results converged to an R factor of 15.0%, with all data between 7 and 1.2 A. The final electron-density map reveals a clear chain tracing with a few disordered residues and five residues out of 58 that present alternate conformations. The Cys14-Cys38 bond presents the less frequently observed left-hand conformation (chi1 = -60 degrees). The solvent molecules and a phosphate ion are well ordered with an average B of 38 A2. The high-resolution structure reveals the N and C termini which were missing from the 1.6 A structure.

Selected figure(s)

Figure 2.
Figure 2 Modeling of Phe17 environment of C5 (red) superimposed with the BPTI molecule of the trypsin (black)/BPTI (blue) complex (2PTC) showing prohibited van der Waals contacts.

Figure 4.
Figure 4 Alternate conformations of (a) Thr2, (b) Asp3, (c) Thr13, (d) Asp16 and (e) Ile18 deduced from the 2F[o] - F[c] electron-density map (1 ).

The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (1998, 54, 306-312) copyright 1998.

Figures were selected by an automated process.