Sulfolobus solfataricus SSO1653
(1Z63, 1Z6A, 1Z5Z)
SSO1653 - snf2 region

The structure of the archaeal Sulfolobus solfataricus Snf2 family member SSO1653 structure 1 is for a 475 residue fragment of the spanning from residue 431 to the C terminus of the native protein. This represents almost exactly the common Snf2 family region.

The polypeptide fragment was crystallised both in the absence (pdb code 1Z6A) and presence of DNA (pdb code 1Z63, fig 1). A third structure encompasses only the C terminal domain at higher resolution (pdb code 1Z5Z).

The fold of each core recA-like domain is substantially similar and related to those of other known SF2 helicases. However, in both the structures with and without DNA the recA-like domain 2 is flipped by some 180 to an arrangement never previously observed for a helicase (fig 2). This unusual orientation in SSO1653 is observed for both the DNA free and DNA-bound forms 1.

nomenclature and source

The structure publication refers to the protein as SsoRad54cd because previous definitions identified Rad54 as the highest homology. the bioinformatic analysis at this site places the protein in an independent SSO1653 subfamily for which it is the achetypal member.

In the Sulfolobus solfataricus P2 strain complete genome, the sequence of this protein is comprised of 2 polypeptides SSO1653 and SSO1655 interrupted by a 48kD transposase SSO1654 inserted between motif IV and V. It is unlikely that the enzyme is active with this insertion, and the transposase appears to be mobile (M White, personal communication). We refer to the fusion of SSO1653 and SSO1655 without transposase as SSO1653.

There is no obvious homologue to S solfataricus SSO1653 in the other two Sulfolobus complete genomes.

structure 1Z6A
description 'SsoRad54cd'
resolution 3.0A
organism Sulfolobus solfataricus
residues 431-906 (end)
DNA no
structure 1Z63
description 'SsoRad54cd:dsDNA'
resolution 3.0A
organism Sulfolobus solfataricus
residues 431-906 (end)
DNA 19 base pairs
structure 1Z5Z
description 'Domain 2'
resolution 2.0A
organism Sulfolobus solfataricus
residues 630-906 (end)
DNA no
database links
PDB 1Z6A, 1Z63, 1Z5Z
PDBsum 1z6a, 1z63, 1z5z
PubMed 15882619
S solfataricus genome SSO1653, SSO1655
NCBI RefSeq NP_343076, NP_343078
SwissProt Q97XQ7, Q97XQ5
Jmol viewer 1z6a, 1z63, 1z5z
features identified in structure
motif I 466-480
motif Ia 499-504
motif II 560-567
motif III 589-594
motif IV 749-759
motif V 806-823
motif VI 838-845
N terminal 431-462
domain 1A 463-631
domain 1B 632-660
domain 2Aa 661-670
domain 2Ba 671-724
domain 2A 725-858
domain 2Bb 859-906
Ib 524-528
Ic 538-545
IIa (switch) 567-574
Hinge 653-660
IVa 780-787
Va 829-831
1: Durr, H., C. Korner, et al. (2005). X-ray structures of the Sulfolobus solfataricus SWI2/SNF2 ATPase core and its complex with DNA. Cell 121(3): 363-73. PubMed