Title:Recombinant Human Semenogelin-1 (Sg1) and Sg1 (1-159) form Detergent Stable Amyloid like Aggregates in vitro
Volume: 23
Issue: 1
Author(s): Neetu Sharma, S Vishwanath and Basant K. Patel
Affiliation:
Keywords:
Amyloid aggregation, Sarkosyl stability, Semenogelin-1, Senile Seminal Vesicle Amyloidosis, Zinc.
Abstract: Senile seminal vesicle amyloidosis (SSVA) is associated with deposition of semenogelin-1
(Sg1) protein aggregates in seminal vesicles that may manifest as hematospermia. Sg1 is the predominant
protein that entraps spermatozoa which are freed upon fragmentation of Sg1 by the protease prostate
specific antigen (PSA), post semen release. Certain small peptide fragments of Sg1 have been reported
to form amyloid aggregates in vitro that can enhance HIV infectivity to cell cultures. However,
the amyloid deposits in the seminal vesicles are expected to be that of the full length Sg1, as PSA is
encountered downstream. So far, amyloid forming ability of full length Sg1 has not been established
in vitro. Here, we examined the amyloidogenicity of full length Sg1 and a large fragment Sg1 (1-159), using recombinant
proteins and tested if Zinc has any effect on their aggregation. Levels of Zinc, which is essential for health of male reproductive
system, gradually decline with age. We succeeded in forming amyloid-like aggregates of Sg1 full length and Sg1
(1-159) fragment showing detergent stability and found that presence of Zn2+ substantially inhibits their amyloid aggregation
in vitro. Possibly, high Zn2+ found in seminal plasma of young individuals may have preventive role against aggregation
of Sg1 in seminal vesicles.