1B20: Deletion of a buried salt-bridge in barnase

Deletion of a buried salt-bridge in barnase. Determined by X-ray diffraction at 1.7 Å resolution. Released 9 Dec 1998.

Method: X-ray diffraction
Resolution: 1.7 Å
Organism: Bacillus amyloliquefaciens
Chains: 3
Atoms: 3,102
Mol. weight: 37.18 kDa
Ligands: ZN
Released: 9 Dec 1998

Explore 1B20 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

1B20 contains 12 α-helices and 21 β-strands across 3 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 4 helices, 7 β-strands

Element	Residues	Length	Sheet
α-helix	7-17	11
β-strand	24-25	2	1
α-helix	27-33	7
α-helix	37-39	3
α-helix	42-45	4
β-strand	50-51	2	1
β-strand	52-56	5	2
β-strand	71-75	5	2
β-strand	87-91	5	2
β-strand	96-99	4	2
β-strand	107-108	2	2

Chains B and C: 4 helices, 7 β-strands

Element	Residues	Length	Sheet
α-helix	7-17	11
β-strand	24-25	2	3
α-helix	27-32	6
α-helix	37-39	3
α-helix	42-45	4
β-strand	50-51	2	3
β-strand	52-56	5	4
β-strand	71-75	5	4
β-strand	87-91	5	4
β-strand	96-99	4	4
β-strand	107-108	2	4

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Protein (barnase)	A, B, C	protein	110	Bacillus amyloliquefaciens	P00648 (AlphaFold model)

Sequence of entity 1 (A, B, C), FASTA

>1B20_1 PROTEIN (BARNASE) (chains A, B, C)
AQVINTFDGVADYLQTYHKLPDNYITKSEAQALGWVASKGNLADVAPGKSIGGDIFSNRE
GKLPGKSGSTWREADINYTSGFRNSDRILYSSDWLIYKTTDHYQTFTKIR

Ligands and cofactors

ID	Name	Formula	Copies
ZN	Zinc ion	Zn	3

Primary citation

A structural double-mutant cycle: estimating the strength of a buried salt bridge in barnase. Vaughan, C.K., Harryson, P., Buckle, A.M. et al. Acta Crystallogr D Biol Crystallogr (2002) 58:591-600. DOI 10.1107/S0907444902001567 · PubMed

Other PDB entries of the same protein (UniProt P00648 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6PQK 1.2 Å, Cryogenic crystal structure of barnase A43C/S80C bound to barstar C40A/S59C/A67C/C82A
2C4B 1.3 Å, Inhibitor cystine knot protein McoEeTI fused to the catalytically inactive barnase…
1A2P 1.5 Å, Barnase wildtype structure at 1.5 Å resolution
2ZA4 1.58 Å, Crystal Structural Analysis of Barnase-barstar Complex
1BRN 1.76 Å, Subsite binding in an RNase: structure of a barnase-tetranucleotide complex at 1.76 Å…
1B2X 1.8 Å, Barnase wildtype structure at PH 7.5 from a cryo_cooled crystal at 100K
1B2S 1.82 Å, Structural response to mutation at a protein-protein interface
1BRI 1.9 Å, Barnase mutant with ile 76 replaced by ala
1RNB 1.9 Å, Crystal structure of a barnase-d(*gp*c) complex at 1.9 Å resolution
1X1Y 1.9 Å, Water-mediate interaction at aprotein-protein interface
3KCH 1.94 Å, Baranase crosslinked by glutaraldehyde
2F5M 1.95 Å, Cross-linked barnase soaked in bromo-ethanol

Browse structure collections

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