[AlbertoA]

amino acetals are easily hydrolized, but nucleosides are amino acetals, why do they don't hydrolize easily?

[fledarmus]

What makes you think they don't?    In fact, that is one of the things that makes them so useful in biological systems. Very small changes in the microenvironment of the cell can lead to large changes in structures of molecules in the cell with the related shifts in function.

[AlbertoA]

What makes you think they don't?    In fact, that is one of the things that makes them so useful in biological systems. Very small changes in the microenvironment of the cell can lead to large changes in structures of molecules in the cell with the related shifts in function.

but, wouldn't it destabilize the dna?

[fledarmus]

There are times when that is precisely what the body needs to do. DNA of aging cells is destroyed and rebuilt into the DNA of new cells. RNA is disassembled and recycled. DNA from other organisms in the food that we eat is absorbed, modified, and rebuilt into our own DNA. DNA from invading microorganisms is torn down and recycled. Glucoside bonds are constantly being made and broken.  Different organelles in the cells maintain different chemical environments to stabilize the nucleoside-sugar bonds where they need to be stabilized, and to break them where they need to be broken.

Most of the chemical bonds that the body uses for its normal day-to-day operation are fairly weak - this enables assembly and disassembly of almost every building block the body uses. The multi-phosphate linkages in ATP and ADP, the amide bonds in proteins, the disulfide bonds in cysteine crosslinks, the hydrogen bonds holding two DNA chains into a double helix, the metal-complex bonds in hemoglobin, all of these the body forms and dissolves as necessary.