Structural Biochemistry Unit: Meet the Team

Nadine Samara - Principal Investigator

Nadine Samara, PhD

Dr. Nadine Samara graduated from the American University of Beirut with a B.S. in Chemistry and became captivated by the idea of using structural biology to visualize enzymes, decipher their mechanism, and understand the basis of their function in biological pathways. Under the mentorship of Dr. Cynthia Wolberger, she obtained a Ph.D. in Molecular Biophysics from The Johns Hopkins University School of Medicine, where she determined high-resolution crystal structures of a transcriptional activator multi-protein enzyme complex called the Deubiquitinating module (DUBm). As a Postdoctoral Fellow in Dr. Wei Yang’s lab at the National Institutes of Health (NIH), she used time-lapse X-ray crystallography to “observe” Ribonuclease H1 (RNase H1) catalyzed hydrolysis of RNA in crystallo. As a Staff Scientist in Dr. Lawrence Tabak’s lab at NIH, Dr. Samara began to study GalNAc transferases (GalNAc-Ts), the enzymes that initiate Mucin Type O-Glycosylation, and made significant contributions to understanding how these enzymes function and recognize their substrates. The Samara lab at NIH was established in 2019 to study the biosynthesis and function of glycans found on both oral microbes as well as in the oral cavity and throughout the digestive tract. The overarching goal of the lab is to use structural, biochemical, and microbiological methods to understand how glycosyltransferases are activated and regulated by co-factors, what their substrates are, how they recognize their substrates, and how these functions evolved from prokaryotes to eukaryotes.

Dr. Lin Shen - Postdoctoral Fellow

Dr. Lin Shen

Dr. Shen received her B.S., her M.S., and her Ph.D. in biochemistry from Lille University, France. She joined the Structural Biochemistry Unit as a visiting fellow in 2020 to start her postdoctoral research at NIDCR/NIH. Dr. Shen is interested in identifying and characterizing the O-Glycosyltransferase machinery that synthesizes exopolysaccharides in oral biofilm. She likes cooking, traveling, and adventurous sports when she is outside the lab.

Dr. Pranav Kumar - Postdoctoral Fellow

Dr. Pranav Kumar

Dr. Kumar obtained his Ph.D. in Structural Biology from The Indian Institute of Technology Roorkee, India in 2019. During his graduate work, he studied the solute binding domain of a bacterial ABC transporter and discovered a unique mechanism of substrate binding. For his postdoctoral research, Dr. Kumar joined the Structural Biochemistry Unit at NIDCR to use structural and biochemical tools to understanding how splicing regulates the function of Drosophila and human GalNAc-Ts. He enjoys reading novels, listening to music, and watching movies.

Dr. Chengxin Li - Postdoctoral Fellow

Chengxin Li

Dr. Li received her Ph.D. in structural biochemistry from Technical University of Denmark in 2021. During her Ph.D. study, she worked on the structural characterization, biosynthesis, and serological interactions of capsular polysaccharides from Streptococcus Pneumoniae. Dr. Li joined the Structural Biochemistry Unit as a visiting fellow to explore novel bacterial exopolysaccharides in oral biofilm and to understand their biosynthetic pathways. Dr. Li enjoys traveling, watching movies, yoga, hiking, and trying different activities.

Caitlyn (Catherine) Murray - Post-baccalaureate Fellow

Photo of Caitlyn Murray

Caitlyn Murray graduated from the Barrett Honors College at Arizona State University in 2025 with a B.S. in biochemistry. In her undergraduate research, Caitlyn studied the mechanism of proton-coupled electron transfer by designing artificial photosynthetic constructs. Caitlyn joined the Structural Biochemistry Unit at NIH to study the structure and biochemical properties of CsaA, a bacterial GalNAc-T like enzyme responsible for the creation of capsular polysaccharides in the pediatric pathogen K. kingae. She likes running, hiking, and gardening.

Nazneen Sultana - Biologist

Photo of Nazneen Sultana

Nazneen Sultana completed her B.S. and M.S. in Microbiology from the University of Dhaka, Bangladesh. She then received her M.S. in Biochemistry from Virginia Tech. Before coming to NIH, Nazneen was working on several projects at the Emory School of Medicine, including understanding the mechanisms of recognition and specific deglycosylation of IgG antibodies by EndoS and EndoS2 from Streptococcus pyogenes to provide a rational basis from which to engineer novel enzymes with antibody and glycan selectivity for clinical and biotechnological applications. She was also studying EndoE, a multi-modular glycoside hydrolase secreted by Enterococcus faecalis, which uniquely combines two enzyme domains with distinct functions and glycan specificities to play a dual role in glycan metabolism and immune evasion. In her most recent project, she studied multiple endoglycosidases from human gut microbes with complementary functions to enhance their ability to adapt and thrive in the diverse environments they may encounter in the human gastrointestinal tract. Before joining Emory University, she was at the Greenwood Genetic Center studying different inherited metabolic disorders and new method development for rare genetic disorders. At Virginia Tech, she studied the structure and function of a flavin-dependent S-monooxygenase from garlic (Allium sativum). Outside of the lab, Nazneen likes to travel, watch movies and series, cook new dishes, and try out different restaurants. 

Lab Alumni

Microbiologist

  • Dr. Robert Palmer (Retired)

Research Fellow

  • Dr. Shuang Li (Health Science Project Manager, NIDCR)

Postbaccalaureate Fellows

  • Gabrielle Law (Graduate student at Harvard University)
  • Susan Schmidt (Graduate student at the University of Minnesota)
  • Abbie Collette (Graduate student at Weill Cornell)
  • Megha Patel (Graduate student at Emory University)

Publications

*Co-author