Structure and function of the N-linked glycans of HBP/CAP37/azurocidin: crystal structure determination and biological characterization of nonglycosylated HBP

TY - JOUR

T1 - Structure and function of the N-linked glycans of HBP/CAP37/azurocidin

T2 - crystal structure determination and biological characterization of nonglycosylated HBP

AU - Iversen, L F

AU - Kastrup, Jette Sandholm Jensen

AU - Bjørn, S E

AU - Wiberg, F C

AU - Larsen, Ingrid K.

AU - Flodgaard, H J

AU - Rasmussen, P B

PY - 1999/10

Y1 - 1999/10

N2 - The three N-glycosylation sites of human heparin binding protein (HBP) have been mutated to produce a nonglycosylated HBP (ng-HBP) mutant. ng-HBP has been crystallized and tested for biological activity. Complete X-ray data have been collected to 2.1 A resolution, and the structure has been fully refined to an R-factor of 18.4% (R(free) 27.7%). The ng-HBP structure reveals that neither the secondary nor tertiary structure have changed due to the removal of the glycosylation, as compared to the previously determined glycosylated HBP structure. Although the primary events in N-linked glycosylation occurs concomitant with polypeptide synthesis and therefore possesses the ability to influence early events in protein folding, we see no evidence of glycosylation influencing the structure of the protein. The root-mean-square deviation between the superimposed structures was 0.24 A (on C alpha atoms), and only minor local structural differences are observed. Also, the overall stability of the protein seems to be unaffected by glycosylation, as judged by the B-factors derived from the two X-ray structures. The flexibility of a glycan site may be determined by the local polypeptide sequence and structure rather than the glycan itself. The biological in vitro activity assay data show that ng-HBP, contrary to glycosylated HBP, mediates only a very limited stimulation of the lipopolysaccharide induced cytokine release from human monocytes. In animal models of fecal peritonitis, glycosylated HBP treatment rescues mice from and an otherwise lethal injury. It appears that ng-HBP have significant effect on survival, and it can be concluded that ng-HBP can stimulate the host defence machinery albeit to a lesser extent than glycosylated HBP.

AB - The three N-glycosylation sites of human heparin binding protein (HBP) have been mutated to produce a nonglycosylated HBP (ng-HBP) mutant. ng-HBP has been crystallized and tested for biological activity. Complete X-ray data have been collected to 2.1 A resolution, and the structure has been fully refined to an R-factor of 18.4% (R(free) 27.7%). The ng-HBP structure reveals that neither the secondary nor tertiary structure have changed due to the removal of the glycosylation, as compared to the previously determined glycosylated HBP structure. Although the primary events in N-linked glycosylation occurs concomitant with polypeptide synthesis and therefore possesses the ability to influence early events in protein folding, we see no evidence of glycosylation influencing the structure of the protein. The root-mean-square deviation between the superimposed structures was 0.24 A (on C alpha atoms), and only minor local structural differences are observed. Also, the overall stability of the protein seems to be unaffected by glycosylation, as judged by the B-factors derived from the two X-ray structures. The flexibility of a glycan site may be determined by the local polypeptide sequence and structure rather than the glycan itself. The biological in vitro activity assay data show that ng-HBP, contrary to glycosylated HBP, mediates only a very limited stimulation of the lipopolysaccharide induced cytokine release from human monocytes. In animal models of fecal peritonitis, glycosylated HBP treatment rescues mice from and an otherwise lethal injury. It appears that ng-HBP have significant effect on survival, and it can be concluded that ng-HBP can stimulate the host defence machinery albeit to a lesser extent than glycosylated HBP.

KW - Animals

KW - Antimicrobial Cationic Peptides

KW - Base Sequence

KW - Blood Proteins

KW - Carrier Proteins

KW - Crystallography, X-Ray

KW - DNA Primers

KW - Glycosylation

KW - Humans

KW - Mice

KW - Polysaccharides

KW - Protein Conformation

KW - Recombinant Proteins

U2 - 10.1110/ps.8.10.2019

DO - 10.1110/ps.8.10.2019

M3 - Journal article

C2 - 10548047

SN - 0961-8368

VL - 8

SP - 2019

EP - 2026

JO - Protein Science

JF - Protein Science

IS - 10

ER -