PDBsum entry 3sxl

RNA binding domain

PDB id: 3sxl

Contents

Protein chains

157 a.a. *

* Residue conservation analysis

PDB id:

3sxl

Name:

RNA binding domain

Title:

Sex-lethal RNA recognition domains 1 and 2 from drosophila melanogaster

Structure:

Protein (sex-lethal). Chain: a, b, c. Fragment: RNA binding domains 1 and 2 (residues 112-294 of full length). Engineered: yes

Source:

Drosophila melanogaster. Fruit fly. Organism_taxid: 7227. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Resolution:

2.70Å R-factor: 0.221 R-free: 0.264

Authors:

S.M.Crowder,R.Kanaar,D.C.Rio,T.C.Alber

Key ref:

S.M.Crowder et al. (1999). Absence of interdomain contacts in the crystal structure of the RNA recognition motifs of Sex-lethal. Proc Natl Acad Sci U S A, 96, 4892-4897. PubMed id: 10220389 DOI: 10.1073/pnas.96.9.4892

Date:

04-Apr-99 Release date: 27-Apr-99

Protein chains

P19339  (SXL_DROME) -  Protein sex-lethal from Drosophila melanogaster

Seq: 354 a.a.

Struc: 157 a.a.

DOI no: 10.1073/pnas.96.9.4892

Proc Natl Acad Sci U S A 96:4892-4897 (1999)

PubMed id: 10220389

Absence of interdomain contacts in the crystal structure of the RNA recognition motifs of Sex-lethal.

S.M.Crowder, R.Kanaar, D.C.Rio, T.Alber.

ABSTRACT

By binding specific RNA transcripts, the Sex-lethal protein (SXL) governs sexual differentiation and dosage compensation in Drosophila melanogaster. To investigate the basis for RNA binding specificity, we determined the crystal structure of the tandem RNA recognition motifs (RRMs) of SXL. Both RRMs adopt the canonical RRM fold, and the 10-residue, interdomain linker shows significant disorder. In contrast to the previously determined structure of the two-RRM fragment of heterogeneous nuclear ribonucleoprotein Al, SXL displays no interdomain contacts between RRMs. These results suggest that the SXL RRMs are flexibly tethered in solution, and RNA binding restricts the orientation of RRMs. Therefore, the observed specificity for single-stranded, U-rich sequences does not arise from a predefined, rigid architecture of the isolated SXL RRMs.

Selected figure(s)

Figure 1.
Fig. 1. Structure of the SXL RRM domains. (A) Sigma-A-weighted, 2F[o] F[c] electron density map contoured at 1 illustrates the quality of the map. Residues shown are Tyr-164-Phe-173. (B) Ribbon diagram of SXL RRM1+2. Residues left out of the model for lack of interpretable electron density include 111-123, 204-205 (interdomain linker), 276-282 ( 2- 4 loop of RRM2), and 290-294 (C terminus). RNP-1 and RNP-2 sequences are colored in magenta. (C) Electrostatic surface potential of SXLl+2 calculated with GRASP (blue = +5 kT > white = 0 kT > red = 5 kT). The absence of interdomain contacts in the SXL RRMl+2 crystal structure is evident. Based on the structures of the RNA complexes of UlA and U2B''/U2A', the most positive regions are likely RNA binding surfaces.

Figure 2.
Fig. 2. Relationship of RRM domains in SXL and hnRNP Al. (A) Ribbon diagrams of Sex-lethal (green) and hnRNP A1 (red) superimposed by using the secondary structural elements of RRM1 of each protein. In contrast to hnRNP A1 RRM2, RRM2 of SXL makes no contacts with RRM1 and differs in orientation from RRM2 of hnRNP A1 by a 92.5° rotation. (B) NMR chemical shift changes for SXL RRM1+2 upon binding the sequence r(GU[8]C) (35). (Left) SXL RRM1+2. (Right) RRM1+2 modeled with the RRM domains arranged as in an hnRNP Al. Chemical shift changes are colored as follows: blue (0-200 Hz), green (201-400 Hz), yellow (401-600 Hz), orange (601-800 Hz), and red (801-1000 Hz). Changes caused by RNA binding are concentrated along the interdomain linker and RNA binding surfaces.

Figures were selected by an automated process.