Any suggestion on Ligating Blunt End libraries?

[lockidi]

My adaptors have 3' C*T bond, to complement A-tailing of gDNA fragment, and 5' P.

I use NEB Quick ligase 5 min at 22C, I also tried Roche for 2 hrs.
TruSeq ligations are much more efficient, they even pick up very small amounts of gDNA. Does anyone have suggestions on how to improve ligation?

Thank you,
D

[jwfoley]

Can you say more about your custom adapters? Illumina's may be more efficient than yours, e.g. the opposite end has a non-complementary Y shape (which can't ligate) and I've heard rumors that the complementary portion may be held together by locked nucleic acids.

Also FYI there's no such thing as "quick ligase"; NEB's Quick Ligation Kit is just regular T4 ligase with a buffer containing polyethylene glycol.