RCSB PDB AI Help Desk: retrieval-augmented generation for protein structure deposition support. - Vivek Reddy Chithari; Jasmine Young; Irina Persikova; Yuhe Liang; Gregg V. Crichlow; Justin W. Flatt; Sutapa Ghosh; Brian P. Hudson; Ezra Peisach; Monica Sekharan; Chenghua Shao; Stephen K. Burley (CoRR, 2026)