PDBsum entry 4oit

Sugar binding protein

PDB id: 4oit

Contents

Protein chains

106 a.a.

Ligands

MAN ×10

BMA

Waters ×130

PDB id:

4oit

Name:

Sugar binding protein

Title:

Structure, interactions and evolutionary implications of a domain- swapped lectin dimer from mycobacterium smegmatis

Structure:

Lysm domain protein. Chain: a, b, c, d. Fragment: mannose-binding lectin domain, unp residues 1-105. Synonym: mannose-binding lectin. Engineered: yes

Source:

Mycobacterium smegmatis. Organism_taxid: 246196. Strain: mc2 155. Gene: msmeg_3662. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.24Å R-factor: 0.222 R-free: 0.261

Authors:

D.Patra,P.Mishra,A.Surolia,M.Vijayan

Key ref:

D.Patra et al. (2014). Structure, interactions and evolutionary implications of a domain-swapped lectin dimer from Mycobacterium smegmatis. Glycobiology, 24, 956-965. PubMed id: 24957055 DOI: 10.1093/glycob/cwu059

Date:

20-Jan-14 Release date: 23-Jul-14

Protein chains

A0QYH7  (A0QYH7_MYCS2) -  Mannose-binding lectin from Mycolicibacterium smegmatis (strain ATCC 700084 / mc(2)155)

Seq: 208 a.a.

Struc: 106 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1093/glycob/cwu059

Glycobiology 24:956-965 (2014)

PubMed id: 24957055

Structure, interactions and evolutionary implications of a domain-swapped lectin dimer from Mycobacterium smegmatis.

D.Patra, P.Mishra, A.Surolia, M.Vijayan.

ABSTRACT

Crystal structure determination of the lectin domain of MSMEG_3662 from Mycobacterium smegmatis and its complexes with mannose and methyl-α-mannose, the first effort of its kind on a mycobacterial lectin, reveals a structure very similar to β-prism II fold lectins from plant sources, but with extensive unprecedented domain swapping in dimer formation. The two subunits in a dimer often show small differences in structure, but the two domains, not always related by 2-fold symmetry, have the same structure. Each domain carries three sugar-binding sites, similar to those in plant lectins, one on each Greek key motif. The occurrence of β-prism II fold lectins in bacteria, with characteristics similar to those from plants, indicates that this family of lectins is of ancient origin and had evolved into a mature system before bacteria and plants diverged. In plants, the number of binding sites per domain varies between one and three, whereas the number is two in the recently reported lectin domains from Pseudomonas putida and Pseudomonas aeruginosa. An analysis of the sequences of the lectins and the lectin domains shows that the level of sequence similarity among the three Greek keys in each domain has a correlation with the number of binding sites in it. Furthermore, sequence conservation among the lectins from different species is the highest for that Greek key which carries a binding site in all of them. Thus, it would appear that carbohydrate binding influences the course of the evolution of the lectin.