Protamine folds DNA into flowers and loop stacks.

ABSTRACT: DNA in sperm undergoes an extreme compaction to almost crystalline packing levels. To produce this dense packing, DNA is dramatically reorganized in minutes by protamine proteins. Protamines are positively charged proteins that coat negatively charged DNA and fold it into a series of toroids. The exact mechanism for forming these ∼50-kbp toroids is unknown. Our goal is to study toroid formation by starting at the "bottom" with folding of short lengths of DNA that form loops and working "up" to more folded structures that occur on longer length scales. We previously measured folding of 200-300 bp of DNA into a loop. Here, we look at folding of intermediate DNA lengths (L = 639-3003 bp) that are 2-10 loops long. We observe two folded structures besides loops that we hypothesize are early int

SUBMITTER: McMillan RB 

PROVIDER: S-EPMC10645571 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature