Which of the following features of the structure of double-stranded DNA is most important in recognition of specific base sequences by most sequence–specific DNA-binding proteins?

The greater depth of the minor groove.

The arrangement of sequence-specific functional groups in the major groove.

The arrangement of sequence-specific functional groups in the minor groove.

The tilt of base pairs in the minor groove.

The tilt of base pairs in the major groove.

The correct answer is: The arrangement of sequence-specific functional groups in the major groove.

To understand why this is the most important feature, let's first consider the structure of double-stranded DNA. DNA consists of two strands, which are formed by a repeating pattern of nucleotides. Each nucleotide contains a sugar molecule (deoxyribose), a phosphate group, and one of four nitrogenous bases: adenine (A), thymine (T), cytosine (C), or guanine (G).

The two strands of DNA are connected via hydrogen bonds between the bases. Specifically, A pairs with T, and C pairs with G, creating base pairs. These base pairs are stacked upon each other, forming a double helix structure. Along the helix, there are two grooves: the major groove and the minor groove.

Now, let's move on to sequence-specific DNA-binding proteins. These proteins have the ability to recognize and bind to specific sequences of DNA. They play important roles in various cellular processes, such as gene regulation.

The major groove of double-stranded DNA provides a larger space compared to the minor groove. This allows for more interactions between the DNA-binding proteins and the nucleotides in the major groove. The arrangement of sequence-specific functional groups, such as hydrogen bond donors and acceptors, is more accessible in the major groove. This enables the DNA-binding proteins to recognize and bind to specific base sequences by forming specific interactions with the nucleotides in the major groove.

In summary, the arrangement of sequence-specific functional groups in the major groove is the most important feature for recognition of specific base sequences by most sequence-specific DNA-binding proteins. This is because the major groove provides a larger space and better accessibility for the proteins to interact with the functional groups in the DNA sequence.

The arrangement of sequence-specific functional groups in the major groove is the most important feature of the structure of double-stranded DNA in recognition of specific base sequences by most sequence-specific DNA-binding proteins.