A Structurally-Validated Multiple Sequence Alignment of 497 Human Protein Kinase Domains

Area of Science:

• Biochemistry
• Structural Biology
• Genomics

Background:

• Protein kinases are crucial regulators of cellular processes.
• Experimental structures are available for only a subset of kinases, limiting functional inference for others.
• Accurate sequence alignment is essential for predicting kinase structures and functions by homology.

Purpose of the Study:

• To develop a precise, structure-based multiple sequence alignment (MSA) for human protein kinase domains.
• To enhance the understanding of kinase structure-function relationships and improve phylogenetic analysis.
• To re-classify kinases based on improved alignment and phylogenetic data.

Main Methods:

• Generated a parsimonious, structure-based MSA of 497 human protein kinase domains.
• Aligned conserved regions and handled variable-length insertions in unaligned blocks.
• Validated alignment accuracy using pairwise, all-against-all alignment of 272 human kinase structures.

Main Results:

• Achieved 97% accuracy in the MSA, with inaccuracies attributed to structural variations and alignment boundaries.
• Identified 17 conserved blocks and interspersed unaligned regions containing key functional motifs (e.g., DFG, HRD).
• Constructed a new human protein kinase domain phylogeny, re-classifying ten 'OTHER' kinases into the CAMK group.

Conclusions:

• The developed MSA provides a robust framework for studying human protein kinases.
• The refined phylogeny clarifies evolutionary relationships and aids in functional annotation.
• This work facilitates a deeper understanding of kinase biology and disease mechanisms.