Nucleotide Architecture Lab

Structural Biochemistry Series: Lesson 1

Student Name:

Date:

January 17, 2026

Part 1: Sugar Pucker Conformations

The pentose ring of DNA and RNA is not planar. It adopts "pucker" conformations to minimize steric hindrance and electrostatic repulsion. Analyze the differences between C2'-endo and C3'-endo puckers.

Conformation A: C2'-endo

[Image: Schematic of C2' atom displaced toward C5']

Commonly found in B-DNA. This conformation increases the distance between phosphate groups.

Describe the effect on the P-P distance compared to C3'-endo:

Conformation B: C3'-endo

[Image: Schematic of C3' atom displaced toward C5']

Commonly found in A-DNA and RNA. The 2'-OH group in RNA sterically favors this pucker.

Why does the presence of a 2'-OH in RNA bias it toward this conformation?

Part 2: Nitrogenous Base Chemistry

Challenge: Nitrogenous bases can exist in different tautomeric forms (e.g., keto vs. enol, amino vs. imino). These rare forms can lead to "mismatches" during replication.

1. Watson-Crick Pair Mapping

Examine a G-C base pair. Circle all hydrogen bond donors (D) and acceptors (A) involved in the interaction.

[Diagram of Guanine]

[Diagram of Cytosine]

H-Bond 1:

H-Bond 2:

H-Bond 3:

2. Tautomeric Transitions

The keto form of Guanine is standard. If Guanine transitions to its rare enol form, how does the donor/acceptor pattern change at the C6 position?

Part 3: Phosphodiester Linkage

The formation of the phosphodiester bond involves a nucleophilic attack by the 3'-OH of the growing chain on the α-phosphate of an incoming dNTP.

Thermodynamic Calculation

Reaction: \( \text{DNA}_n + \text{dNTP} \rightarrow \text{DNA}_{n+1} + \text{PP}_i \)

Why is the hydrolysis of pyrophosphate (\( \text{PP}_i \)) by pyrophosphatase essential for DNA synthesis in vivo?

DNA is chemically more stable than RNA at alkaline pH. Explain this observation using the 2'-OH group in your mechanism.

End of Lab Sheet - Please return to your lab station to begin the molecular modeling portion.

Nucleic Acid Chemistry and Function

Nucleotide Chemistry and Polymerization

DNA Topology and Supercoiling

DNA-Protein Interactions

RNA Structure and Catalysis

Sequencing and Synthetic Nucleic Acids

Nucleotide Architecture Lab Worksheet

Building Blocks of Life Slides

Nucleotide Chemistry Masterclass Teacher Guide

DNA Under Pressure Slides

Tying the Knot Exercises Worksheet

Topological Stress Simulation Guide

Molecular Handshakes Slides

Lac Operon Interface Case Study

DNA Binding Motifs Chart Reference

Versatile Ribozyme Slides Deck

Folding RNA Models Workshop Worksheet

RNA World Debate Discussion Guide Teacher

Reading the Code Slides Deck

Viral Probe Design Project Worksheet

Nucleic Acid Mastery Quiz Assessment

Similar Sequences

Lab Chemistry Mastery

Olutoyin Makinde

The Digital Launch

brittaink@urbandaleschools.com

The Identity Studio

brittaink@urbandaleschools.com

Innovation Lab: Identity Studio

brittaink@urbandaleschools.com

Exposure Mastery

Landry.Stahl

Sticky Matter

Hadlee Richardson

Electron Empire

ssneierson

Square Sage Mastery

mr.sigma

Signal and Story

Tom Ingram

Service Sync

Marlyce Kemp

Efficiency Engine

Matthew.Sprout

Sense Detectives

Michele Magee

Web Interactiva

Norman René Trujillo Zapata

Magnetic Forces Investigation

Olutoyin Makinde

Circuit Mastery

Olutoyin Makinde

Maîtrise ICT Expert

Molecular Frontiers

Tanya Salman

Chemistry Core

Taryn Sigl

Chemical Conversions Mastery

worton

Blueprinting the Air

jmoulison

Retail Career Quest

Tia Washington

Atomic Architecture

Marsha Bolden

Pressure Power

Olutoyin Makinde

Cyber Sentry Prep

Nick Masoner

Body Systems 101

Tanya Salman