PDBsum entry 3q6t

Protein binding

PDB id: 3q6t

Contents

Protein chains

381 a.a.

Ligands

CIT

Waters ×48

PDB id:

3q6t

Name:

Protein binding

Title:

Salivary protein from lutzomyia longipalpis, ligand free

Structure:

43.2 kda salivary protein. Chain: a, b. Fragment: unp residues 19-399. Engineered: yes

Source:

Lutzomyia longipalpis. Sand fly. Organism_taxid: 7200. Gene: ljm11_clu9. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.93Å R-factor: 0.197 R-free: 0.246

Authors:

J.F.Andersen,X.Xu,B.W.Chang,N.Collin,J.G.Valenzuela,J.M.Ribeiro

Key ref:

X.Xu et al. (2011). Structure and function of a "yellow" protein from saliva of the sand fly Lutzomyia longipalpis that confers protective immunity against Leishmania major infection. J Biol Chem, 286, 32383-32393. PubMed id: 21795673 DOI: 10.1074/jbc.M111.268904

Date:

03-Jan-11 Release date: 27-Jul-11

Protein chains

Q5WPU9  (Q5WPU9_LUTLO) -  43.2 kDa salivary protein from Lutzomyia longipalpis

Seq: 399 a.a.

Struc: 381 a.a.

DOI no: 10.1074/jbc.M111.268904

J Biol Chem 286:32383-32393 (2011)

PubMed id: 21795673

Structure and function of a "yellow" protein from saliva of the sand fly Lutzomyia longipalpis that confers protective immunity against Leishmania major infection.

X.Xu, F.Oliveira, B.W.Chang, N.Collin, R.Gomes, C.Teixeira, D.Reynoso, V.My Pham, D.E.Elnaiem, S.Kamhawi, J.M.Ribeiro, J.G.Valenzuela, J.F.Andersen.

ABSTRACT

LJM11, an abundant salivary protein from the sand fly Lutzomyia longipalpis, belongs to the insect "yellow" family of proteins. In this study, we immunized mice with 17 plasmids encoding L. longiplapis salivary proteins and demonstrated that LJM11 confers protective immunity against Leishmania major infection. This protection correlates with a strong induction of a delayed type hypersensitivity (DTH) response following exposure to L. longipalpis saliva. Additionally, splenocytes of exposed mice produce IFN-γ upon stimulation with LJM11, demonstrating the systemic induction of Th1 immunity by this protein. In contrast to LJM11, LJM111, another yellow protein from L. longipalpis saliva, does not produce a DTH response in these mice, suggesting that structural or functional features specific to LJM11 are important for the induction of a robust DTH response. To examine these features, we used calorimetric analysis to probe a possible ligand binding function for the salivary yellow proteins. LJM11, LJM111, and LJM17 all acted as high affinity binders of prohemostatic and proinflammatory biogenic amines, particularly serotonin, catecholamines, and histamine. We also determined the crystal structure of LJM11, revealing a six-bladed β-propeller fold with a single ligand binding pocket located in the central part of the propeller structure on one face of the molecule. A hypothetical model of LJM11 suggests a positive electrostatic potential on the face containing entry to the ligand binding pocket, whereas LJM111 is negative to neutral over its entire surface. This may be the reason for differences in antigenicity between the two proteins.