ABSTRACT
Heat shock protein Hsp40 is a stress protein with chaperone activity and has a cooperative function with Hsp70 in mammalian cells. We examined the possible expression of Hsp40 in lung tumor tissues using immunoblotting and immunohistochemistry, and established an enzyme-linked immunosorbent assay (ELISA) method to detect IgG antibody to Hsp40 in the serum using purified human Hsp40. Sera were obtained from 130 normal subjects and 50 patients with lung cancer. Lung tumor tissues and cells specifically overexpressed Hsp40, and no such expression was detected in normal lung tissues. Compared with normal sera, significantly higher levels of autoantibody to Hsp40 were present in patients with lung cancer. The present study is the first to demonstrate overexpression of Hsp40 in human tumor tissue and the associated presence of autoantibody to Hsp40 in the serum. These results suggest that overexpression of Hsp40 in tumor cells may be recognized as a self-antigen.
Subject(s)
Autoantibodies/blood , Heat-Shock Proteins/analysis , Heat-Shock Proteins/immunology , Lung Neoplasms/immunology , Lung Neoplasms/pathology , Adenocarcinoma/pathology , Carcinoma, Small Cell/pathology , Carcinoma, Squamous Cell/pathology , Enzyme-Linked Immunosorbent Assay , HSP40 Heat-Shock Proteins , Humans , Immunoglobulin G/blood , Immunohistochemistry , Lung/immunology , Lung/pathology , Lung Neoplasms/blood , Reference ValuesABSTRACT
Fructose-1,6-/sedoheptulose-1,7-bisphosphatase of Synechococcus PCC 7942, overexpressed from Escherichia coli, has been purified and crystallized by the hanging-drop vapour-diffusion method using ammonium sulfate as a precipitant. The crystals were monoclinic, with unit-cell parameters a = 80.1, b = 84.2, c = 104.3 A, beta = 101.7 degrees. They belonged to space group P2(1) and diffracted to at least 2.2 A resolution. The calculated V(M) value, based on a tetramer in the asymmetric unit, was 2.2 A(3) Da(-1).
Subject(s)
Cyanobacteria/enzymology , Phosphoric Monoester Hydrolases/chemistry , Crystallization , Crystallography, X-Ray , Phosphoric Monoester Hydrolases/isolation & purification , Protein ConformationABSTRACT
A novel pectolytic enzyme, polymethoxygalacturonase SX1 from Trichosporon penicillatum, with a molecular weight of 36 kDa was crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 1000 as a precipitant. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 165.6, b = 61.0, c = 48.7 A, beta = 93.1 degrees. The calculated V(M) based on one molecule per asymmetric unit was 3.40 A(3) Da(-1). A native data set was collected to 2.08 A resolution from a crystal on a Cu Kalpha rotating-anode X-ray source. A molecular-replacement solution was obtained using the program AMoRe and the structure of endopolygalacturonase II from Aspergillus niger as a model.
